New Mars Forums
You are not logged in.
- Topics: Active | Unanswered
Announcement
#201 Re: Human missions » Near Earth Object (NEO) missions » 2008-05-14 08:49:04
The energetics say it all. Launching from the equator of a 1 km radius asteroid with a rotation period of 10 hours gives a velocity boost of 0.62 kms/hr.
#202 Re: Human missions » Problems with Humans on Mars » 2008-05-14 06:50:18
JonClarke,
Your proposition was "Per kg they are faster cheaper and better than robots". For purely human abilities such as creativity, imagination, intuition and insight that's obviously true because robots don't currently posses those abilities, and maybe never will. For insitu sensing and analysis even MER class robots are many orders of magnitude cheaper than people. Such robots can be cheaply distributed globally around Mars. Human missions will initially be focused on small areas and will have to rely on satellites, remote networks and rovers to explore beyond their landing zone.
Nobody would seriously doubt the efficiency of satellite sensing, once upon a time people did remote sensing using aircraft. Robots in orbit are clearly far superior to humans in aircraft. The same is now true for remote and insitu sensing on Mars. Human explorers on Mars will use robots as tools for sensing and analysis both locally and remotely, their time will be too valuable for such tasks.
Sample return is not about the robot coming back, it's about returning a sample. The robot that collects the sample will probably stay on the surface.
8 hours of pure exploration work per mission day is quite efficient for a person. Consider the travel time to site, setting up camp, sleeping etc etc. And that's not including mission preparation time. ISS crews spend the majority of their waking time just maintaining their environment and their health. EVAs are particularly time consuming. Even with the expected improvements in suits, EVAs on Mars will be very inefficient compared with a geologist free to walk in the open air.
To compare the cost per kg of a MER rover (yes, about $2.5m) with the cost of crew time on ISS is ignoring the cost of the ISS which is just as vital to their mission as the system that got the MERs to the surface. Three crew weigh about 250 kg, launch costs are trivial compared to the cost of the ISS that they depend on. Add that in and they cost about $120m/kg (assuming an ISS cost of $30billion)
#203 Re: Unmanned probes » Cassini-Huygens - NASA/ESA Saturn orbiter & Titan lander » 2008-05-14 05:30:06
Long-lived Storm - 29 Apr 2008
It is no Great Red Spot, but these two side-by-side views show the longest-lived electrical storm yet observed on Saturn by NASA's Cassini spacecraft.
The views were acquired more than three months after the storm was first detected from its lightning-produced radio discharges on Nov. 27, 2007. See PIA08410 for an earlier color view of this storm. Cassini imaging scientists believe the storm to be a vertically extended disturbance that penetrates from Saturn's lower to upper troposphere.
The view at left was created by combining images taken using red, green and blue spectral filters, and shows Saturn in colors that approximate what the human eye would see. The storm stands out with greater clarity in the sharpened, enhanced color view at right. This view combines images taken in infrared, green and violet light at 939, 567 and 420 nanometers respectively and represents an expansion of the wavelength region of the electromagnetic spectrum visible to human eyes. This view looks toward the un-illuminated side of the rings from about 3 degrees above the ringplane. Janus (181 kilometers, or 113 miles across) appears as a dark speck just beneath the rings in both images.
These images were obtained with the Cassini spacecraft wide-angle camera on March 4, 2008, at a distance of approximately 1.3 million kilometers (800,000 miles) from Saturn. Image scale is 74 kilometers (46 miles) per pixel.
#204 Re: Human missions » Problems with Humans on Mars » 2008-05-14 03:16:39
Excuse me. I am a scientist and I am strongly in favour of people exploring Mars. Per kg they are faster cheaper and better than robots.
Humans require much more overhead than robots: air, water, food etc etc. and they usually want to come back again. Humans can only work efficiently for about 8 hours per day. They are certainly not cheaper per kg and for many tasks not faster or better either. Furthermore, robots are rapidly improving, humans are not.
#205 Re: Interplanetary transportation » Ares I (CLV) - status » 2008-05-14 01:36:26
J-2X Moving Into CDR - 13 May 2008
Frank Morring, Jr./Aerospace Daily & Defense Report
NASA's J-2X rocket engine development project is moving into critical design review (CDR) with extensive data on the performance of its Saturn-heritage gas generator and turbomachinery, holding pace for first flight of the Ares I crew launch vehicle.
Engineers at Stennis Space Center, Miss., ran the last of nine hot-fire tests of an old J-2 powerpack May 8, firing the unit for 400.45 seconds and throttling it up and back to generate data points for the J-2X upgrade (Aerospace DAILY, May 9). The results - with Saturn-era J-2 turbomachinery pulled from the XRS-2200 linear aerospike engine Pratt & Whitney Rocketdyne developed for Lockheed Martin's X-33 testbed - demonstrate the value of using old hardware to develop new.
"It certainly has been a great opportunity to get some early data at a fairly high level of assembly - it's not a full engine - that has really benefitted our design cycle prior to CDR," says Tom Byrd, deputy manager of the J-2X upper stage engine project. "It gives us a real leg up to know that we're starting with a mission-proven design that actually worked for moon missions. It tells us quite a bit about how that heritage design can then be modified for the J-2X."
That gives the Ares I project a leg up in developing the J-2X as its upper stage engine. The engine is considered the pacing item for the entire launch vehicle, although that may change if the Orion crew exploration vehicle development schedule slips to give engineers more time to develop weight-saving hardware (Aerospace DAILY, May 12).
So far, Byrd says, the engine project is on track to support a first flight in 2013. The hot-fire testing at the historic A-1 test stand at Stennis - built for Saturn V engine testing and used extensively by the space shuttle main engine (SSME) project - worked out kinks in the test setup that should smooth the second round of powerpack tests in April 2010 with flight-configuration inlet ducts and pumps.
While the original J-2 produced 230,000 pounds of thrust powering the upper stage of the Saturn V, the J-2X is intended to generate 294,000 pounds of thrust. Design of that upgraded hardware will draw on performance data from the test series just concluded to upgrade overall engine performance to meet the needs of the Ares I, which will deliver six astronauts to the International Space Station and - eventually - four to the first leg of a human return to the moon.
The J-2X project plans about 22 "Powerpack 2" tests with flight-configuration hardware in the spring of 2010, followed immediately by full-up J-2X engine tests. Some 200 full-up tests are planned, which makes test-stand efficiency key to bringing in a flight engine on time. To hasten the work, the J-2X project has an agreement with the SSME project to take over the A-2 stand at Stennis in July 2009 and begin refitting it for testing in tandem.
Already under construction at Stennis is a new A-3 test stand for simulated-altitude testing of the extended nozzle that the J-2X will carry to boost its specific impulse. It is scheduled to come on line in September 2010
#206 Re: Space Policy » Griffin tells Mars researchers a few truths » 2008-05-13 17:12:47
There probably was a good reason for the law, whatever it was. NASA can lobby the President but not Congress. It seems to make sense and balances agency power.
One day far far in the future, there will be missions to other stellar systems to colonize other Earth like planets - missions to the Outer planets will be just local trips 
#207 Re: Unmanned probes » Solar Probe+ » 2008-05-13 13:33:54
The extraordinary mission trajectory!
From Mission Engineering Study Report (PDF 39MB) - 10 Mar 2008
#208 Re: Unmanned probes » Phoenix - North Pole Region Lander (PHX) » 2008-05-13 10:17:59
Thin black ellipses indicate expected landing zone - there's a 99% chance of landing inside the outermost one
Topography and Terrain of Phoenix Target Area - 13 May 2008
This shaded relief map shows the topography and color-coded types of terrain in and around the targeted landing site for NASA's Mars Phoenix Lander.
The spacecraft will reach Mars on May 25, 2008. The center of the targeted landing area is at the center of the set of ellipses superimposed on the map. Plans call for navigating Phoenix to hit a target at the top of Mars' atmosphere so that the spacecraft will have a 66 percent chance of landing within the smallest of the three ellipses and a 99 percent chance of landing within the largest of the three.
An impact crater informally named "Heimdall" lies in the orange-coded area northeast of the targeted landing site. The crater is about 10 kilometers (6 miles) wide. Material ejected from Heimdall has been mapped as a rocky inner portion (orange) and an outer portion (yellow). The outer ejecta is relatively rock-free, as is the "lowland bright" unit (light blue), which is probably an even farther-out portion of where material ejected from Heimdall has been deposited. These two ejecta units thus provide a rock-free and flat terrain for the Phoenix landing.
The "lowland dark" (dark blue) unit has more rocks detectable from orbit than the lowland bright unit.
More details and images from the press conference today - 13 May 2008
During the press conference it was stated that the first signal after touchdown is expected within one minute of landing at 23:53 UTC ERT. It will contain EDL and other engineering data. The radio is then turned off as the relay satellites will be out of range. Next signal, including the first image, is expected 90 minutes later. These are nominal timings.
#209 Re: Interplanetary transportation » Orion (CEV / SM) - status » 2008-05-13 09:03:59
CEV Parachute Assembly System (CPAS); Variable Porosity. Continuous Ribbon (VPCR)
From Status Report on the Parachute Development (PDF 4MB) - dated 29 Feb 2008
Each Parachute Stage is designed for a single parachute failure
Philosophy is that 1 Drogue Parachute and 2 Main Parachutes are primary landing system
Additional drogue and Main are deployed in parallel to simplify parachute control (no fault detection required)
Drogue Parachutes are initiated at an appropriate altitude and a Mach number less than 0.8
Following Drogue parachute release, Pilot parachutes are mortar deployed and initiate Main parachute deployment
#210 Re: Human missions » Near Earth Object (NEO) missions » 2008-05-13 08:51:41
Nasa plans landing on 40m-wide asteroid - 7 May 2008 - by Ian Sample
It was once considered the most dangerous object in the universe, heading for Earth with the explosive power of 84 Hiroshimas. Now an asteroid called 2000SG344, a lump of rock barely the size of a large yacht, is in the spotlight again, this time as a contender for the next giant leap for mankind.
Nasa engineers have identified the 1.1m tonne asteroid, which in 2000 was given a significant chance of slamming into Earth, as a potential landing site for astronauts, ahead of the Bush administration's plans to venture deeper into the solar system with a crewed voyage to Mars.
The mission - the first to what officials call a Near Earth Object (NEO) - is being floated within the US space agency as a crucial stepping stone to future space exploration.
A report seen by the Guardian notes that by sending astronauts on a three-month journey to the hurtling asteroid, scientists believe they would learn more about the psychological effects of long-term missions and the risks of working in deep space, and it would allow astronauts to test kits to convert subsurface ice into drinking water, breathable oxygen and even hydrogen to top up rocket fuel. All of which would be invaluable before embarking on a two-year expedition to Mars.
Under the Bush administration, Nasa has been charged with sending astronauts back to the moon, beginning in 2020 and culminating in a permanent lunar outpost, itself a jumping off point for more distant Mars missions. With the agency's ageing fleet of space shuttles due to be retired soon after 2010, the agency has begun work on a replacement called Orion and a series of Ares rockets that will blast them into orbit.
In a study due to be published next month, engineers at Nasa's Johnson Space Centre in Houston and Ames Research Centre in California flesh out plans to use Orion for a three to six month round-trip to the asteroid, with astronauts spending a week or two on the rock's surface.
As well as giving space officials a taste of more complex missions, samples taken from the rock could help scientists understand more about the birth of the solar system and how best to defend against asteroids that veer into Earth's path.
"An asteroid will one day be on a collision course with Earth. Doesn't it make sense, after going to the moon, to start learning more about them? Our study shows it makes perfect sense to do this soon after going back to the moon," said Rob Landis, an engineer at Johnson Space Centre and co-author of the report, which is due to be published in the journal Acta Astronautica.
More precise measurements of the orbit of 2000SG344 have allayed fears that it could hit Earth sometime around the end of September 2030, but the asteroid is still expected to come close in astronomical terms.
The report lays out plans for a crew of two to rendezvous with a speeding asteroid that is due to pass close by Earth. After a seven-week outward journey, the Orion capsule would swing around and close in on the rock.
#211 Re: Unmanned probes » Solar Probe+ » 2008-05-13 03:08:21
Finally, after all this time!
APL to Send a Probe to the Sun - 1 May 2008
The Johns Hopkins University Applied Physics Laboratory is sending a spacecraft closer to the sun than any probe has ever gone – and what it finds could revolutionize what we know about our star and the solar wind that influences everything in our solar system.
NASA has tapped APL to develop the ambitious Solar Probe mission, which will study the streams of charged particles the sun hurls into space from a vantage point within the sun’s corona – its outer atmosphere – where the processes that heat the corona and produce solar wind occur. At closest approach Solar Probe would zip past the sun at 125 miles per second, protected by a carbon-composite heat shield that must withstand up to 2,600 degrees Fahrenheit and survive blasts of radiation and energized dust at levels not experienced by any previous spacecraft.
Experts in the U.S. and abroad have grappled with this mission concept for more than 30 years, running into seemingly insurmountable technology and budgetary limitations. But in February an APL-led team completed a Solar Probe engineering and mission design study at NASA’s request, detailing just how the robotic mission could be accomplished. The study team used an APL-led 2005 study as its baseline, but then significantly altered the concept to meet challenging cost and technical conditions provided by NASA.
“We knew we were on the right track,” says Andrew Dantzler, Solar Probe project manager at APL. “Now we’ve put it all together in an innovative package; the technology is within reach, the concept is feasible and the entire mission can be done for less than $750 million [in fiscal 2007 dollars], or about the cost of a medium-class planetary mission. NASA decided it was time.”
APL will design and build the spacecraft, on a schedule to launch in 2015. The compact, solar-powered probe would weigh about 1,000 pounds; preliminary designs include a 9-foot-diameter, 6-inch-thick, carbon-foam-filled solar shield atop the spacecraft body. Two sets of solar arrays would retract or extend as the spacecraft swings toward or away from the sun during several loops around the inner solar system, making sure the panels stay at proper temperatures and power levels. At its closest passes the spacecraft must survive solar intensity more than 500 times what spacecraft experience while orbiting Earth.
Solar Probe will use seven Venus flybys over nearly seven years to gradually shrink its orbit around the sun, coming as close as 4.1 million miles (6.6 million kilometers) to the sun, well within the orbit of Mercury and about eight times closer than any spacecraft has come before.
125 miles per second (200 kms/sec) - that's ridiculous speed!
#212 Re: Human missions » International Space Station (ISS / Alpha) » 2008-05-13 01:59:29
New Water Reclamation System Headed for Duty on Space Station - 12 May 2008
HUNTSVILLE, Ala. -- International Space Station crews soon will have a new water reclamation system that will recycle wastewater, allowing up to six crew members to live aboard the orbiting laboratory.
The latest addition to the station's life support system departs today from NASA's Marshall Space Flight Center in Huntsville, Ala., to NASA's Kennedy Space Center, Fla., for final flight preparations.
The new Water Recovery System, or WRS, is the second part of a comprehensive life support system for the station. It is scheduled to fly aboard space shuttle Endeavour on STS-126 targeted for later this year. The first part of the system, the Oxygen Generation System, was launched on shuttle Discovery in July 2006. The two systems are part of NASA's Regenerative Environmental Control and Life Support System, or ECLSS, for the station.
"Recycling will be an essential part of daily life for future astronauts, whether on board the space station or living on the moon," said Mike Suffredini, the station program manager. "Delivering this hardware is an important step in achieving the station's full potential, allowing for additional crew members and more scientific research."
By recycling, the system reduces the dependence on Earth resupply by cutting the amount of water and consumables needed to be launched by about 15,000 pounds, or 6,800 kilograms, a year.
"As early as the late 1960's we knew sustaining life in space would require recycling water and oxygen," said Bob Bagdigian, ECLSS project manager. "A number of us have experienced the entire lifecycle of this technology, all the way from early ideas to implementation. Knowing that we will soon see this system completed, gives us great pride."
Through a series of chemical treatment processes and filters, the Water Recovery System creates water clean enough to drink. In fact, part of the same process has been used in Third World countries to produce drinkable water.
A distillation process is used to recover water from urine. The process occurs within a rotating distillation assembly that compensates for the absence of gravity, aiding in the separation of liquids and gases in space. Once distilled, the water from the urine processor is combined with other wastewaters and delivered to the water processor for treatment.
The water processor removes free gas and solid materials such as hair and lint, before the water goes through a series of filtration beds for further purification. Any remaining organic contaminants and microorganisms are removed by a high-temperature catalytic reaction. These rigorous treatment processes create water that meets stringent purity standards for human consumption.
Engineers at Marshall and at Hamilton Sundstrand Space Systems International Inc., Windsor Locks, Conn., led the design and development of the Water Recovery System.
#213 Re: Human missions » Armstrong Lunar Outpost - status » 2008-05-13 01:45:44
"The latest solar cells are about 30% efficient."
If solar cells are so efficient, why is it that the ISS solar cells apparently work at about 4%? 100 kilowatts for 2500 square meters?
Bob
The 30% refers to the efficiency of converting solar energy into electricity. The ISS arrays were designed and built several years ago, typical silicon cells at that time were about 20% efficient. Today the latest triple junction cells are about 30%. Future cells based on CNT should reach 45%.
#214 Re: Human missions » Armstrong Lunar Outpost - status » 2008-05-12 15:29:32
Don't forget the difference in albedo, the Earth (0.37) reflects about three the light of the Moon (0.12)
Stellarium tells me the maximum magnitude of the Earth as seen from the Moon is -16.2 and the Moon appears at max magnitude -12.2 from the Earth - a difference of 4 magnitudes or 2.5^4 or about 39 times brighter.
#215 Re: Human missions » Armstrong Lunar Outpost - status » 2008-05-12 12:30:02
The latest solar cells are about 30% efficient. Given tracking they can produce amazing amounts of power, each ISS pair of solar arrays produces about 30 KW. However the problem is mass, they are big and need more structural support when on the moon, they also need power conditioning and distribution hardware. They will need to be cleaned of lunar dust. So it's a trade of mass, size and performance. A 40 KW reactor has a mass of about 5 MT and operates continuously. Nuclear power will probably be necessary for processing water ice inside a permanently shadowed crater.
#216 Re: Human missions » STS-124 Discovery » 2008-05-12 11:20:16
(05/10/2008) --- CAPE CANAVERAL, Fla. -- Workers in the payload changeout room on Launch Pad 39A at NASA's Kennedy Space Center check space shuttle Discovery's payload bay doors as they close around the Japanese Experiment Module—Pressurized Module
#218 Re: Unmanned probes » Phoenix - North Pole Region Lander (PHX) » 2008-05-12 11:00:39
SSI will serve as Phoenix's "eyes" for the mission, providing high-resolution, stereo, panoramic images of the martian arctic. Using an advanced optical system, SSI will survey the arctic landing site for geological context, provide range maps in support of digging operations, and make atmospheric dust and cloud measurements.
Situated atop an extended mast, SSI will provide images at a height two meters above the ground, roughly the height of a tall person. SSI simulates the human eye with its two optical lens system that will give three-dimensional views of the arctic plains. The instrument will also simulate the resolution of human eyesight using a charged-coupled device that produces high density 1024 x 1024 pixel images. But SSI exceeds the capabilities of the human eye by using optical and infrared filters, allowing multispectral imaging at 12 wavelengths of geological interest and atmospheric interest.
Looking downward, stereo data from SSI will support robotic arm operations by producing digital elevation models of the surrounding terrain. With these data, scientists and engineers will have three-dimensional virtual views of the digging area. Along with data from the TEGA and the MECA, scientists will use the three-dimensional views to better understand the geomorphology and mineralogy of the site. Engineers will also use these three-dimensional views to command the trenching operations of the robotic arm. SSI will also be used to provide multispectral images of samples delivered to the lander deck to support results from the other scientific instruments.
Looking upward, SSI will be used to estimate the optical properties of the martian atmosphere around the landing site. Using narrow-band imaging of the Sun, the imager will estimate density of atmospheric dust, optical depth of airborne aerosols, and abundance of atmospheric water vapor. SSI will also look at the lander itself to assess the amount of wind-blown dust deposited on spacecraft. Deposition rates provide important information for scientists to understand erosional and atmospheric processes, but are critical for engineers who are concerned about the amount of deposited dust on the solar panels and associated power degradation.
Like the eyebrows?
13 days
#219 Re: Space Policy » NASA 2009 Budget » 2008-05-12 10:40:55
It's in the 2009 Budget request:
Resources in the Exoplanet Exploration Program will be used to assess different techniques and mission concepts for detecting and characterizing extrasolar planets, including space-based astrometric, coronagraphic, and statistical concepts.
A new medium-class Exoplanet mission, managed by the Jet Propulsion Laboratory, will begin formulation in 2010, for which a re-scoped version of Space Interferometry Mission (SIM) is being evaluated as a potential candidate. $271.8M is available within Other Missions and Data Analysis for this mission ($6.6M in FY09, $41.7M in FY10, $44.0M in FY 11, $72.0M in FY12 and $107.5M in FY13).
The Keck Interferometer has been delivered for community use, and NASA's partnership in the Keck Observatory is being renewed.
The Large Binocular Telescope Interferometer (LBTI) will be reviewed during FY 2009 to ensure satisfactory progress and support from the appropriate agency.
Kepler is scheduled to launch in February 2009.
The program maintains a technology line as Terrestrial Planet Finder (TPF) funds now reside in a new "Exoplanet Exploration Technology" line.
#220 Re: Intelligent Alien Life » Why is the Universe silent? » 2008-05-12 10:36:19
Exactly so Bob. Those tales of doom and gloom are nothing to worry about. According to the global warming alarmists the Earth's surface temperature is increasing by 6°C per century, so in about 100,000 years the Earth will be a ball of plasma.
#221 Re: Pictures of Mars » Real images of Mars » 2008-05-12 10:17:08
Atmospheric break-up could result in clusters or chains ...
Breakup of a meteor in the atmosphere would be most unlikely to result in a linear chain, especially in an atmosphere as thin as Mars. Tidal disruption of the body before entering the atmosphere seems the most likely cause of similar size chain craters. Secondary craters are usually sorted in decreasing size and point back to the original impact crater.
#222 Re: Science, Technology, and Astronomy » Titan » 2008-05-12 10:11:42
Reminiscent of noctilucent clouds.
#223 Re: Science, Technology, and Astronomy » Super heavy elements found in nature » 2008-05-12 10:08:18
At the risk of irritating you Vincent, temperature and pressure are not factors inside the nucleus. They are macro properties of molecules. Temperature is the molecular kinetic energy, and pressure is the force these molecules exert externally.
It's the strong nuclear force that dominates inside the atom, the stability of a nucleus is determined by this force.
#224 Re: Human missions » Armstrong Lunar Outpost - status » 2008-05-12 07:17:30
1. Yes, and that's the current plan, nuclear power isn't being considered for many years. See the sample campaign for the first ten years. Initially crews will only stay for a few weeks and use solar power, when energy storage is available they will extend missions out to six months.
2. Producing water comes after oxygen generation and power. Even if water ice is found in the dark craters it probably won't be used for a while because of the extreme difficulty in extracting and transporting it. Closed life support systems will probably precede ISRU. It seems unlikely that we'll be able to jump ahead to food production early on unless there are rapid advances in ISRU.
More details:
Crew & Habitat Consumables (Crew of 4) .......... Amount (kg/yr)
Oxygen Consumed in Hab by crew & leakage ..........2924.0
EVA oxygen (1kg O2*72 EVAs*4CM/180 days) ..........576.0
Total O2 Needed ...................................................3500.0Nitrogen Makeup N2 for leakage and airlock losses ....554.0
Water Mostly closed loop make-up .............................90.0
No water recycling ................................................3898.2
EVA water (4kg H2O 72 EVAs*4 CM/180 days) ........1152.0Total water (no recycling) ......................................5050.2
Total water (w/ recycling) ......................................1242.0Total Gas Inflate habitat (any gas - one time) .........1800.0
Without recycling the Outpost needs about 9MT of gases and water per year
#225 Re: Intelligent Alien Life » Why is the Universe silent? » 2008-05-12 06:20:40
What causes random changes to the axis? Probably giant impacts, the Moon won't stop those.
The day night cycle and the associated temperature changes cause cyclical changes at different strength scales on Earth, many are far stronger than lunar tides. It doesn't seem necessary to have lunar gravity to begin life.