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Once again the James Webb Space Telescope is delayed to 2020 and is facing a cost overrun which may bust the budget cap. The problem this time is some of the directional thrusters are "contaminated?" This is after the unfurling and refurlling of the heat sunshade designed to keep the satellite cold.
In a statement by Rep. Lamar Smith (Republican, TX), the chairman of the House Science Committee: "These continued delays and cost overruns undermine confidence in NASA and it's prime contractor, Northrup Grumman."
If the overruns exceed the budget cap and the house declines to renew or augment funding, the entire project is subject to cancellation. The amount spent on another NASA white elephant project is $8 Billion.
IMHO: NASA needs to stop trying to make promises it cannot keep; the space telescope was far too complex and at a location which precludes a manned servicing mission. I love what it was promised to do.
Added in edit: this situation makes the projected WFIRST telescope look a lot more promising--and affordable.
Last edited by Oldfart1939 (2018-03-27 22:00:02)
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Oldfart1939,
Projects like JWST, SLS, and Orion are the only reason why NASA has no funding for "real space exploration" missions, or merely sending humans into LEO again, for that matter. There's an extreme "cart / horse" problem at NASA. Their contractors pull them in every conceivable direction because there's no coherent program to accomplish anything worth doing. JWST was and is a worthy project, but not at a cost of $8B. If the technology is so complicated and sensitive that it's just not ready for prime time yet, then focused development programs should test new technologies until they're ready for use in a mission. Every major project the agency has undertaken since STS has been absurdly over budget. That's the problem with using cost-plus contracts to develop mission hardware. There's no incentive on the part of the contractor to minimize costs.
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Cost-plus is entirely appropriate when what you are attempting is something not done before. Fixed-fee is appropriate for doing things that already well-known and well defined. There is a spectrum of things between those two extremes. JWST is partly never-done-before and partly done-before-on-Hubble, etc. It shouldn't have been one giant contract program.
SLS is building a Saturn-5-equivalent out of shuttle hardware tinkertoys. There's no real never-done-before content in that, other than trying to tame the combustion instabilities in the 5-segment SRB's. I can understand why that has been costly, as that has never before been done at this size, in an already-fully-metallized propellant. That leaves only mods to the grain bore shapes to adjust. In total, the program really isn't very much about actually flying a giant rocket, it's corporate welfare for the entire shuttle contractor base. Kinda shows, don't it?
Orion is building Apollo 30% larger with more modern avionics, but no lander, and a foreign-built (undersized) service module. There's nothing new there, either. No excuse for it to be so expensive, or to have taken so long. More corporate welfare for the "old space" contractor base. Shows rather badly, don't it?
GW
ps -- got the staples out this morning. doing well.
Last edited by GW Johnson (2018-03-28 10:39:19)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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GW-
In response to your 2 "kinda shows badly": Yup!
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We did have an older topic James webb which captured some of the unobtanium cost over runs through the past decade and it does not surprise me that cost plus is striking out again to a contractor that was not cable of providing the product in the first place.
https://www.washingtonpost.com/news/spe … yed-again/
It's yet another setback for the ambitious but beleaguered mission, which has been in the works since 1996. The cost of the mission quickly ballooned past the initial projection of about $1 billion, and the launch was pushed back from 2007 to 2008, then 2009, then 2010, then 2011, then 2013, then 2014, then 2015 or maybe 2016. The delay may increase the cost of the mission to beyond the $8 billion funding cap established by law.
https://www.pbs.org/newshour/science/ja … gthy-delay
For more than a generation, astronomers have been waiting for the James Webb Space Telescope, NASA’s successor to the iconic Hubble Space Telescope. On Tuesday they learned they will have to wait even longer, as agency officials revealed Webb’s launch date has slipped from spring of 2019 to approximately May of 2020—a delay that could cost hundreds of millions of dollars, breaching the $8.8 billion telescope’s Congressionally-mandated cost cap and requiring legislators to either provide more funding or abandon the project.
The calamity of errors are:
Valves on the spacecraft’s thrusters had sprung leaks after being improperly cleaned, and replacing them had taken the better part of a year.
five-layered folding “sunshield” had also been torn during a test as it unfurled, requiring time-consuming failure analyses and repairs.
This was the sales pitch:
Unlike Hubble, which resides in low-Earth orbit and has been kept alive by repeated servicing missions, Webb would be stationed beyond the orbit of the moon and cooled nearly to absolute zero by its sunshield. Its mission would last until it runs out of fuel in five to 10 years.
From its lofty perch Webb’s sophisticated infrared instruments and giant 6.5-meter mirror would see what Hubble never could: the universe’s very first stars and galaxies, embryonic star systems mid-formation in cosmic wombs of gas and dust, and the atmospheres of planets orbiting other stars.
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Chinese plan to reverse engineer and copy the ideas of James Webb Space Telescope ...hopefully not soon and not before JWST gets launched?
https://twitter.com/stromgade/status/13 … 7533497348
JWST is the telescope of the future, it is beyond cutting edge, it was probably overly complex, multiple partners across the world, complex flattening and unfolding system, it still will be beyond cutting edge ...but... what caused all the delay and why has China been allwed to catch up with the USA.
People here remember the old newmars discussions on the next Hubble, they also remember a time when it was supposed to be launched in 2007.
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They tend to do that with just about every thing including reports of a starship...…
The way that the telescope is gaining magnification is the most unique in that its taking small mirrors to simulate the large un-launchable that would be required to perform in this unit.
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Webb telescope launch date slips again
https://arstechnica.com/science/2021/06 … ips-again/
Black Hole Keeps Evading Detecting and Scientists Can't Explain It
https://science.slashdot.org/story/21/0 … explain-it
That mystery could be solved by Hubble's successor — NASA's big, powerful James Webb Space Telescope, which is scheduled to launch in October 2021. If James Webb doesn't spot a black hole in the galaxy's heart or in one of its bigger stellar clumps, "then the best explanation is that the black hole has recoiled well out of the center of the galaxy," NASA officials wrote.
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launch on a European Ariane 5 rocket from a spaceport in French Guiana
its been a case of picking an untried design with an unknown contractor that had never made a telescope let alone one of this size.
equaling cost overruns and lots of repair work to get it right....
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Another delay?
We have old topics on newmars that show it was to launch all the way back in 2007
it once had a 500-million-dollar budget
It will have 6 times larger in area than Hubble. It is so large it is made in 18 pieces that fold together during the launch, so that it can fit into a rocket. It is mainly an infrared telescope but also works in the red part of the visible light (the pictures will be coded with false color so we can see them). The JWST will be in orbit far from Earth, to avoid heat radiating from the Earth and moon. This special orbit is beyond the moon, at the second Lagrange point (L2) of the Sun-Earth system, a place of stable gravity. It is plated with gold because gold reflects infrared very well. It will be able to see things that the Hubble Space Telescope cannot. It is protected by a large sunshield the size of a tennis court to keep it cool and dark.
JWST launch slips to November
https://spacenews.com/jwst-launch-slips-to-november/
“Earth Cousins” Are New Targets for Planetary Materials Research
https://eos.org/opinions/earth-cousins- … s-research
For example, observing Earth-analogue exoplanets—that is, Earth-sized planets orbiting within the habitable zone of their host stars—is difficult today and will remain so even with the next-generation James Webb Space Telescope (JWST) and large-aperture ground-based telescopes. In coming years, it will be much easier to gather data on—and to test hypotheses about the processes that generate and sustain habitability using—“Earth cousins.” These small-radius exoplanets lack solar system analogues but are more accessible to observation because they are slightly bigger or slightly hotter than Earth.
Scientists discover new exoplanet with an atmosphere ripe for study
https://eurekalert.org/pub_releases/202 … 060821.php
Past research suggests planets this cool may have clouds high in their atmospheres, which makes it hard to determine what types of gases surround them. But new observations of another small, cool planet called K2-18 b broke this trend and showed evidence of water in its atmosphere, surprising many astronomers.
"TOI-1231 b is one of the only other planets we know of in a similar size and temperature range, so future observations of this new planet will let us determine just how common (or rare) it is for water clouds to form around these temperate worlds," said Burt.
Additionally, with its host star's high Near-Infrared (NIR) brightness, it makes an exciting target for future missions with the Hubble Space Telescope (HST) and the James Webb Space Telescope (JWST). The first set of these observations, led by one of the paper's co-authors, should take place later this month using the Hubble Space Telescope.
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Billions and Years Later Than Originally Expected, it is Finally Ready For Launch?
NASA's James Webb Space Telescope is Ready for Space!
https://www.labroots.com/trending/chemi … eady-space
https://twitter.com/RedSharkNews/status … 6134332417
Last edited by Mars_B4_Moon (2021-09-07 08:55:20)
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James Webb Space Telescope has a launch date!!
From French Guiana aboard an Ariene V launch vehicle, 18 December 2021.
Only a "few years late, and over budget."
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James Webb Space Telescope will reveal new insights into astrochemistry
https://phys.org/news/2021-11-james-web … eveal.html
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The launch has been delayed from December 22nd to the 24th, due to electrical problems between the satellite and the launch vehicle.
https://www.yahoo.com/news/james-webb-t … 16089.html
BBC
James Webb telescope lifted atop its launch rocket
Jonathan Amos - BBC Science Correspondent
Tue, December 14, 2021, 7:21 PM
This article for the general public includes details about the launch, including use of air vents in the fairing to insure pressure decreases evenly as the vehicle ascends.
(th)
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This thing is squarely in the same ballpark as the purchase price of a nuclear powered aircraft carrier. If it fails in any significant way, then it's a non-repairable 8 billion dollar piece of space junk.
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For kbd512 re #15
According to (my memory of ) the presentation Saturday at the North Houston NSS meeting, there are over 100 single-point-of-failure events that must occur.
I asked Google for a more accurate count, and it came up with "over 300" ...
The Road to Launch and Beyond for NASA's James Webb Space ...
www.nasa.gov › feature › goddard › the-road-to-launch-and-beyond-for-n...
Nov 2, 2021 · Following launch, over 300 single point failure items and 50 major deployments must work to ensure optimal science. Webb's first deployment, the ...
How The James Webb Space Telescope Will Deploy (In An Ideal ...
www.forbes.com › sites › startswithabang › 2018/01/26 › how-the-james-w...
Jan 26, 2018 · Here are the critical steps it must take to be science-ready. ... A rough launch-and-deployment timeline of the James Webb Space Telescope.
I noticed the wiggle term "optimal science" so degraded performance is (presumably) still possible if any of those 300 fail.
If the instrument succeeds, it ** should ** live as long as an aircraft carrier, whose mission is supported by on going and never ending maintenance.
(th)
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At present, no nation has a man capable vehicle that could reach the L2 point with enough consumables to support a repair team. We are talking about a mission that lasts for weeks. Musk's Starship could eventually do it. But his vehicle is as yet unproven and a mission like this is unprecedented. Working in the cold of the moon's shadow would present its own challenges. Carrying out delicate work in a space suit would also be tough. I wonder if it would be possible to surround the telescope with an inflatable envelope for the duration of the work?
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
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This thing is clearly not ready to launch yet, and quite probably will fail somewhere during the deployment of all those moving pieces.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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For Gw Johnson re Webb launch ...
The key technology that is of ** direct ** impact on the Mars venture is the radiative cooling to 50 Kelvin.
Achievement of ** that ** milestone would be a major advance for shipment of liquid oxygen and liquid methane to Mars on a vessel designed to use them there for orbit capture or for landing.
SpaceNut has been reminding forum readers for as long as I've been here (and probably before) that at present there exists ** NO ** passive technology to avoid boil-off. The Webb team have had to confront that bugaboo in order to protect the infrared sensor and the near-infrared sensor from heat from all sources.
Even if nothing else worked, and ** that ** technology ** did ** work, I would count the entire 9 billion investment as well worth the expense.
Having a reliable stash of liquid propellants will increase chances of success of Mars bound vessels, and the same is true for the return trip, when even ** more ** propellant is needed to achieve a smooth orbit in LEO without the dreaded aerobraking.
Aerobraking ** must ** be removed from all spacecraft design except as a last chance technology when all else has failed.
(th)
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Aerobraking ** must ** be removed from all spacecraft design except as a last chance technology when all else has failed.
I think the truth of that or not depends upon the nature of the aerobraking. Direct entry-and-landing is quite a different scenario from aerobraking to capture into orbit. It also depends upon how big a delta-vee you are trying to dissipate on any one pass.
The heat shield for direct entry off interplanetary trajectories looks like the heat shield used by Apollo returning from the moon, more-or-less. For direct entry at Mars, you get in the way of the planet which then runs over you from behind due to orbital speed difference about the sun, while gravity accelerates you toward Mars. Depending upon your trajectory, speed relative to Mars at entry interface varies between about 5.6 km/s to 7.5 km/s.
Mars escape is only 5 km/s. You have to enter at a shallow angle to make this work without smacking the surface before any drag deceleration can occur, and still not bounce off into space to b e lost forever. It is tricky, and it it quite demanding on the heat shield, and on the structures. Several gees' deceleration are usually involved.
The same direct entry scenario at Earth return is similar, but more demanding. The orbital speed differences are such that you are trying to smack into the Earth from behind it, while gravity further accelerates you toward the Earth. Depending upon your trajectory, your speed at entry interface can range from about 12 km/s to almost 17 km/s. Earth escape is only 11 km/s. You have to enter at a shallow angle, but still not bounce off into space to be lost forever. In comparison, Apollo coming back from the moon hit the entry interface at about 10.9 km/s. It pulled 10-11 gees doing that.
The delta-vees for aerobraking are the entry speed less the Mach 3 speed for end-of-hypersonics: about 1 km/s on Earth, and about 0.7 km/s on Mars. That puts the direct-entry aerobraking delta-vees at around 4.9 to 6.8 km/s at Mars, and about 11 to almost 16 km/s at Earth. It was 9.9 km/s for Apollo coming back from the moon, and it is around 6.9 km/s coming back from LEO.
For aerobraking capture into orbit, you must get from entry interface speed down to your capture orbit periapsis speed IN ONE PASS!!! Fail, and you zing back out into space above local escape, to be lost forever. That periapsis speed is greater than low circular orbit speed, but still less than escape. I have not run the numbers, but I'd guess about 4.5 km/s at Mars and about 9.9 km/s at Earth, using 90% of local escape. That puts you into a very elongated elliptical capture orbit, with a very long period, and low stability against the disturbing pull of 3rd bodies. But, your periapsis is still deep in the atmosphere, so on each pass you aerobrake toward a low circular orbit down in the atmosphere meaning you are aerobraking pass-by-pass toward entry and landing.
Under those approximate assumptions, the first-pass aerocapture delta-vee requirement is interface speed minus periapsis speed. For Mars that would be 1.1 to 3 km/s, which is lower than the direct-entry delta-vee range of 4.9 to 6.8 km/s. For Earth, that would be 2.1 to 7.1 km/s, vs 11 to 16 km/s for direct entry. Those aerobrake 1st-pass delta-vee ranges are lower than the direct-entry delta-vees, yes, but not that much less. Actually, the higher end of each range is comparable to entry from low circular orbit, something we already know requires a substantial heat shield: 3 vs 3.6 km/s at Mars, and 7.1 vs 7.9 km/s at Earth.
You won't be able to skim the outer atmosphere and slow down by these numbers. You WILL have to dive deeper down to get the decelerations, which means you will suffer heating, and you will pull some significant gees. Earth's upper atmosphere varies in properties a little bit. Mars varies by a factor of 2. You have to carefully monitor Mars's upper atmosphere in order to calculate just how deep to go to get 1st-pass delta-vee reliability for aerobraking into capture orbits.
But for an orbit-to-orbit ship, it is Earth arrival that you have to size your heat shield for. And at 12-17 km/s entry speed, you must use ablatives; re-radiating refractories cannot work! Not only is there whopping loads of radiant plasma heating to contend with, that plasma sheath is essentially opaque to any re-radiant emission you might otherwise create. That happens at about 10 km/s, in any atmosphere.
GW
Last edited by GW Johnson (2021-12-15 16:42:33)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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we are be off for the Telescope.
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Liftoff from the Guiana Space Center is now scheduled for Dec. 25 at 7:20 a.m. ET, weather permitting.
Weighing a mere 13,700 pounds, the giant, next-generation telescope, which is named after a former NASA administrator, will take 29 days to reach its destination and complete a complex unfolding procedure. Months of calibration will follow before the telescope can begin taking photos of the early universe.
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Myself, I think the deployment is very likely to screw up. I also think it likely that they won't be able to fix all the screw-ups from the ground. Which necessitates a repair mission.
Question 1 -- if SLS/Orion cannot reach Earth L2 to mount a repair mission on JWST, then what good is it?
Question 2 -- if SLS/Orion can reach Earth L2, then just exactly how is an astronaut going to anchor himself in order to exert the forces necessary to make "whatever" repairs. SLS/Orion does NOT have a manipulator arm with handholds and footholds on it.
Just asking.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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This topic is one of two that contains the word Webb ... It is no longer appropriate, since Webb is on station, but I decided not to create a new topic....
https://www.youtube.com/watch?v=fPdKUObyhw4
There appears to be a web site dedicated to tracking Webb ... the YouTube able appears to show live data, but it may just be a snapshot.
If someone has time, please look for the web site and post a link here. The site appears to report on temperature on the cold side, which is the reading that is most relevant to success of the mission. The cold side needs to drop to (about) 50 Kelvin.
(th)
Recruiting High Value members for NewMars.com/forums, in association with the Mars Society
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The James Webb telescope is included in the list of instruments who contributed to the study reported at the link below.
One of the elements discovered in the observations is tellurium.
>
> https://www.cnn.com/2023/10/25/world/we … 8316047748
(th)
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