Dragon Lunar Flyby and more

SpaceNut · 2016-02-29 22:02:22

Pulling out the question of

Terraformer wrote:

Could we fly Dragon around Luna? It's designed to return from Mars, after all. How soon could an unmanned test be done? How big would a service module have to be for a manned flyby?
I'd really like to see a manned Lunar mission in the next few years...

SpaceNut · 2016-02-29 22:04:04

RobertDyck wrote:

Falcon Heavy could launch Dragon on a flyby past the Moon. It would have to be a free return trajectory. Dragon doesn't have enough propellant to enter lunar orbit, certainly not enough to leave. Dragon was originally designed by SpaceX for their bid for CEV. It had a service module, to enter lunar orbit today and return it would need a service module to replace its trunk. But they could do a free return flyby as it is now.

RobS · 2016-02-29 22:04:59

It's probably possible with a Falcon Heavy. There might be tourist money to be made that way!

SpaceNut · 2016-02-29 22:10:37

I find the idea interesting and did a quick google to see if other forums have been discussing the same realm of thought and here is what I found...

Solo lunar flyby using standard falcon 9 and dragon

Translunar Dragon Flights?

Lunar Mission Profiles for Commercial Space Operations

SpaceNut · 2016-03-02 22:16:00

http://www.spacex.com/sites/spacex/file … ev_2.0.pdf

http://www.spacex.com/sites/spacex/file … tSheet.pdf

http://www.spacex.com/dragon
Total Launch Payload Mass
6,000kg 13,228 lbs
Height With Trunk
7.2m2 3.6 ft
Diameter
3.7m 12 ft

Total Launch Payload Volume
25m3 883 ft3
Spacecraft Payload Volume
11m3 388 ft3
Trunk Payload Volume
14m3 494 ft3

http://www.spacex.com/falcon9

Payload to LEO
13,150kg 28,991 lb
Payload to GTO
4,850kg 10,692 lb

http://www.spacex.com/falcon-heavy
Payload to LEO
53,000kg 116,845 lb
Payload to Mars
13,200kg 29,101 lb
Payload to GTO
21,200kg 46,738 lb

kbd512 · 2016-03-04 10:19:06

If Falcon Heavy can push 16t through TLI, is an orbital mission also feasible or is the dV requirement for orbital insertion and return too high?

Terraformer · 2016-03-04 14:02:21

I think orbital insertion and exit would add an extra 5km/s to the delta-V requirement, so no - if you're only using one stage.

However, perhaps launching two stages would enable such a mission? With hydrolox, that 32 tonnes should allow a Dragon capsule to brake into orbit and be returned.

I'd really like to see a landing, just to demonstrate that we still have the right stuff, but that's harder still.

On the other hand, putting everything together - Bigelow modules, Falcon Heavy, Dragon capsules, inflatable heat shields - could we do a demonstration mission that *wouldn't* involve throwing away everything except the capsule? That is, have the service module use a heat shield to aerobrake into LEO.

Well, I can dream.

kbd512 · 2016-03-04 14:31:32

Terraformer,

If all you have is an extended LOX/RP-1 upper stage from one Falcon Heavy mated to a capsule and lander delivered by another Falcon Heavy, is there enough storable propellant aboard Dragon to return to Earth?

All I want to do is land near the Apollo 11 lander site for one day, take pictures and video, and tell the deniers to get bent.

RobertDyck · 2016-03-04 21:47:25

According to this webpage, Apollo 12 delta-V (ft/2):
TLI: 10,515
MCC: 61.8
LOI: 2,889.5
TEI: 3,042.0

Using these figures, what would Dragon need to enter lunar orbit, and return to Earth? Remember Apollo first launched into Earth orbit, then TLI burn pushed it into trans-lunar trajectory. Falcon Heavy is capable of direct-throw to TLI. So you need Mid-Course Correction (MCC), Lunar Orbit Insertion (LOI), and Trans-Earth Injection (TEI).

Hint: Orion uses the SLS upper stage for LOI. The ATV-based service module is only capable of TEI. The first Orion service module was to use liquid methane and liquid oxygen (LCH4/LOX). SpaceX is developing a big rocket engine to use that propellant mix. And two companies were contracted to develop LCH4/LOX engines for Orion. They each built prototypes that could be used as RCS thrusters, and both said they could scale-up to service module main engine.

RobertDyck · 2016-03-04 21:57:03

kbd512 wrote:

All I want to do is land near the Apollo 11 lander site for one day, take pictures and video, and tell the deniers to get bent.

Google Lunar X-Prize?
Guidelines

Apollo Heritage Bonus Prize - $4 million will be awarded to a team that can produce an Apollo Heritage Mooncast from the site of Apollo 11, 12, 14, 15, 16, or 17. The Mooncast must include eight minutes of dynamic video in both high definition and lower resolution near real time video, a panoramic photo of the Apollo site, and an image showing a substantial portion of the craft from the Apollo site.

SpaceNut · 2016-03-04 22:14:20

The saturn v used the third stage for the earth departure stage....which pushed the capsule, service module and LM on its way.
I would modify the Dragon Truck into a LM and Launch a Dragon as well as the new LM both on a Falcon 9 heavy to allow for an addition fuel stage to be add to both as if to make a third stage for pushing the combo from orbit once they are docked together in earth orbit. Use the LM fuel stage to push us to the moon and the Dragons to return us to earth once more. The new Lm acts as additional space on the trip both ways until we begin to enter earth orbit on the way back.

RobertDyck · 2016-03-04 23:32:43

I would design a custom lunar module. Apollo LM used aluminum alloy honeycomb to reduce weight. It had a problem that it was only rated for 5 depressurize/repressurize cycles. What is the ISS Quest Airlock made of? What is the EVA hatch made of? I seem to remember video of astronauts leaving the Shuttle airlock, and the hatch looked floppy. Could an LM pressure hull use composite material, and still be rated for multiple depress/repress cycles? Remember it has to deorbit, safely land, then ascend again. Apollo LM used the descent module for deorbit and landing. Russian LK used their block G stage for both LOI, and deorbit. They used the LK propulsion stage (called block E) for both landing and ascent. The LK had legs that jettisoned during ascent. Soyuz LOK service module was used for TEI only. Orion will now use the SLS upper stage for LOI, the ATV-based service module will be used for TEI only. Sounds like the Russian system. How much surplus delta-V will the Falcon Heavy upper stage have? Could it be used for TLI, LOI, and deorbit? That upper stage uses RP-1/LOX, will propellants remain without boil-off to the Moon? Is there danger of RP-1 gelling, due to cold from LOX? According to SpaceX, Falcon Heavy upper stage is capable of multiple engine starts. The Russian Block G used RP-1/LOX.

In 2011, estimates were Falcon Heavy would lift 16,000kg to TLI, or 14,000kg to TMI. Today SpaceX says Falcon Heavy payload to Mars is 13,200kg.

Dragon dry mass: 4,200kg. Propellant 1,290kg. The only statement on Dragon v2 claimed dry mass will be the same, but I find that hard to believe. The crew version will include seats, controls, life support, launch abort system, and propellant for LAS. As well as landing feet, and hydraulics to deploy them. Composites could compensate for some of the mass gain, but I expect total launch mass will be heavier than Dragon v1. However, this gives us something to work with.

RobertDyck · 2016-03-05 13:27:03

Again to compare the Soviet mission plan from the 1960s to NASA's plan.

             Soviet    Apollo            Constellation         EM-1            EM-2
Earth orbit: Block V   S-IVB(burn 1)     Ares V/I upper stage  ICPS (5m DCSS)  EUS
TLI:........ Block G   S-IVB(burn 2)     Ares V upper stage    ICPS            EUS
outbound MCC Block D   Apollo SM         Orion SM              ATV-based SM    EUS
LOI:........ Block D   Apollo SM         Altair descent stage  ATV-based SM    EUS
deorbit:.... Block D   LM descent stage  Altair descent stage  N/A             N/A
landing:.... Block E   LM descent stage  Altair descent stage  N/A             N/A
ascent:..... Block E   LM ascent stage   Altair ascent stage   N/A             N/A
TEI:........ Soyuz SM  Apollo SM         Orion SM              ATV-based SM    ATV-based SM
inbound MCC: Soyuz SM  Apollo SM         Orion SM              ATV-based SM    ATV-based SM

Originally, NASA talked about EM-1 using the Orion SM for LOI. Then in 2012 they talked about a lunar flyby, not entering orbit at all. Looks like current plan for EM-1 is gravity assist, then enter "distant retrograde orbit (not circular)", then departure burn, then gravity assist to TEI.

Historical comparison: Constellation animation

Last edited by RobertDyck (2016-03-06 00:51:56)

SpaceNut · 2016-03-05 21:44:05

We sure do know how to land on the moon as seen in all of the successes

Well for a lunar landing by a new LM we would need to know some math. http://www.nasa.gov/pdf/466759main_AP_E … anding.pdf its for high schoolers but then again here is the http://www.mathematica-journal.com/2012 … thematica/

Of course one we are there we need a different equation to ascend back to orbit to remate up with the waiting Dragon in lunar orbit.

https://en.wikipedia.org/wiki/Escape_velocity

2.4 Ve (km/s)

http://www.braeunig.us/space/orbmech.htm

So for the free return we would use Calculus Investigation: The Slingshot Around the Moon.
http://courses.ncssm.edu/math/NCSSM%20S … 3/Moon.pdf

kbd512 · 2016-03-06 05:00:01

RobertDyck wrote:

I would design a custom lunar module. Apollo LM used aluminum alloy honeycomb to reduce weight. It had a problem that it was only rated for 5 depressurize/repressurize cycles. What is the ISS Quest Airlock made of? What is the EVA hatch made of? I seem to remember video of astronauts leaving the Shuttle airlock, and the hatch looked floppy. Could an LM pressure hull use composite material, and still be rated for multiple depress/repress cycles? Remember it has to deorbit, safely land, then ascend again. Apollo LM used the descent module for deorbit and landing. Russian LK used their block G stage for both LOI, and deorbit. They used the LK propulsion stage (called block E) for both landing and ascent. The LK had legs that jettisoned during ascent. Soyuz LOK service module was used for TEI only. Orion will now use the SLS upper stage for LOI, the ATV-based service module will be used for TEI only. Sounds like the Russian system. How much surplus delta-V will the Falcon Heavy upper stage have? Could it be used for TLI, LOI, and deorbit? That upper stage uses RP-1/LOX, will propellants remain without boil-off to the Moon? Is there danger of RP-1 gelling, due to cold from LOX? According to SpaceX, Falcon Heavy upper stage is capable of multiple engine starts. The Russian Block G used RP-1/LOX.

I rather like the "pumpkin" lander concept that Northrop-Grumman worked on for the Golden Spike Company.

RobertDyck wrote:

In 2011, estimates were Falcon Heavy would lift 16,000kg to TLI, or 14,000kg to TMI. Today SpaceX says Falcon Heavy payload to Mars is 13,200kg.

For Falcon Heavy to get that kind of performance, propellant cross-feed is required and the reusability hardware has to be removed.

RobertDyck wrote:

Dragon dry mass: 4,200kg. Propellant 1,290kg. The only statement on Dragon v2 claimed dry mass will be the same, but I find that hard to believe. The crew version will include seats, controls, life support, launch abort system, and propellant for LAS. As well as landing feet, and hydraulics to deploy them. Composites could compensate for some of the mass gain, but I expect total launch mass will be heavier than Dragon v1. However, this gives us something to work with.

Dragon v2 wet mass is probably closer to 8t+.

SpaceNut · 2016-03-06 11:21:29

This topic is sort of a question on how do we do Apollo with COTS as we try to get the commercial market to want to go and do space without the governement funding.

So we have launch vehicles, soon to be capable of using manned capsule, cargo capsules, bigelow inflateables ect... but what they would need is a lunar lander to be able to do what Nasa has already done.

I would say with a few tweeks that we could do the lunar flyby using spacex hardware and launchers but we would not be able to do a moon landing as we still need that cots ability.

https://en.wikipedia.org/wiki/Apollo_Lunar_Module
http://www.space.com/17411-apollo-11-mo … aphic.html
http://history.nasa.gov/diagrams/apollo.html
http://www.apolloproject.com/diagrams/diagrams.html

So to start a build for a cots lander we might make use of the cygnus module or the Dragon and make modifications to each to create a lander for a short stay sortie mission as a first step towards a commercial market.

Cygnus modification are more extensive than that of what we need for the dragon as the cygnus have no cability for landing or ascent once we are on the moons surface.

Dragon would need a landing stage as the capsule has the ability to ascend back to orbit. The unpressurized truck area would make for such a landing stage to be designed within as I can see it.

SpaceNut · 2016-03-07 22:56:01

Spacex and the Moon?

http://exoscientist.blogspot.com/2012/0 … -cost.html

SpaceX has said two Falcon Heavy launches would be required to carry a manned Dragon to a lunar landing. However, the 53 metric ton payload capacity of a single Falcon Heavy would be sufficient to carry the 40 mT (Earth departure stage + lunar lander) system described below. This would require 30 mT and 10 mT gross mass Centaur-style upper stages. The "Delta-V budget" page gives the delta-V from LEO to low lunar orbit as 4,040 m/s. In calculating the delta-V provided by the larger Centaur stage we'll retain 1,000 kg propellant at the end of the burn for the return trip of this stage to LEO: 465.5*9.8ln((30,000 + 10,000 + 4,000)/(3,000 +10,000 + 4,000 + 1,000)) = 4,077 m/s, sufficient to reach low lunar orbit. For this stage alone to return to LEO, 1,310 m/s delta-V is required. The 1,000 kg retained propellant provides 465.5*9.8ln((3,000 + 1,000)/3,000) = 1,312 m/s, sufficient for the return.
The delta-V to go from low lunar orbit to the Moon's surface is 1,870 m/s. And to go from the Moon's surface back to LEO is 2,740 m/s, for a total of 4,610 m/s. The delta-V provided by this smaller Centaur stage is 465.5*9.8ln((10,000 + 4,000)/(1,000 + 4,000)) = 4,697 m/s, sufficient for lunar landing and the return to LEO.

SpaceNut · 2016-06-30 22:24:30

NASA Is Putting SpaceX's Crew Dragon Through The Wringer

Making sure the capsule performs well under pressure

All of that means the pressure vessel has to be vigorously tested on a brand new spacecraft like SpaceX's Crew Dragon. The Crew Dragon is shaping up to be the first privately owned vehicle to carry astronauts to the space station next year or in 2018

Another kind of pressure test, which NASA's Orion capsule recently underwent, overfills the capsule with air, exposing any weaknesses in the pressure vessel structure as it expands

SpaceNut · 2016-11-10 20:59:56

I thinks its time to dream of doing more than go around in the ISS circle. To which I would like use the Dragon for lunar flyby tourism flights or for going to a lunar hotel or even to its surface to do ISS style science on its surface.
Even if all we can do is tourism flights its not really enough for anyone to make much money from doing so. The flights to stay steady would need to be really low in cost in order to last for any period of time.

The launch vehicle for the space X dragon means we need to define the orbital conditions for launches to mat up the intended pieces at and by chosing it we start to determine the level of mass that we can bring to any level. So orbital time of assembly also become important as we neeed to know how many chunks are needed to pull this mission off.

Some pieces would be reuseable while others would not be for all mission styles to lunar area.

With a lunar Red dragon design setting on a spent first stage of new design to allow for a lunar landing could the red dragon get back to orbit assuming minimal mass remains from a mission to the moon.

SpaceNut · 2017-02-03 21:07:36

This topic and the Apollo 8 Redux is mostly falling along the same discusion area.

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#1 2016-02-29 22:02:22

Dragon Lunar Flyby and more

#2 2016-02-29 22:04:04

Re: Dragon Lunar Flyby and more

#3 2016-02-29 22:04:59

Re: Dragon Lunar Flyby and more

#4 2016-02-29 22:10:37

Re: Dragon Lunar Flyby and more

#5 2016-03-02 22:16:00

Re: Dragon Lunar Flyby and more

#6 2016-03-04 10:19:06

Re: Dragon Lunar Flyby and more

#7 2016-03-04 14:02:21

Re: Dragon Lunar Flyby and more

#8 2016-03-04 14:31:32

Re: Dragon Lunar Flyby and more

#9 2016-03-04 21:47:25

Re: Dragon Lunar Flyby and more

#10 2016-03-04 21:57:03

Re: Dragon Lunar Flyby and more

#11 2016-03-04 22:14:20

Re: Dragon Lunar Flyby and more

#12 2016-03-04 23:32:43

Re: Dragon Lunar Flyby and more

#13 2016-03-05 13:27:03

Re: Dragon Lunar Flyby and more

#14 2016-03-05 21:44:05

Re: Dragon Lunar Flyby and more

#15 2016-03-06 05:00:01

Re: Dragon Lunar Flyby and more

#16 2016-03-06 11:21:29

Re: Dragon Lunar Flyby and more

#17 2016-03-07 22:56:01

Re: Dragon Lunar Flyby and more

#18 2016-06-30 22:24:30

Re: Dragon Lunar Flyby and more

#19 2016-11-10 20:59:56

Re: Dragon Lunar Flyby and more

#20 2017-02-03 21:07:36

Re: Dragon Lunar Flyby and more

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