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Red Dragon
Paolo
post Aug 7 2011, 09:46 AM
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'Red Dragon' Mission Mulled as Cheap Search for Mars Life
any opinion on this? would it really make sense adapting a manned spaceship to unmanned Mars landing? I am skeptical...

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Mongo
post Sep 17 2012, 05:17 PM
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That's the big question -- whether it would be more cost-effective to use a nearly stock Dragon, with its very low cost, to deliver a science cargo of several tonnes to the Martian surface, or to design a vessel specifically for Mars, which could deliver a substantially larger payload to Mars surface but at a much greater cost.

My guess is that a specially designed landing vehicle plus Falcon Heavy launcher could deliver maybe six tonnes of scientific payload to the Martian surface in a single package, but would cost as much as three separate two-tonne payload Red Dragon landers plus launchers.
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Kaputnik
post Sep 17 2012, 08:39 PM
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A 'nearly stock' Dragon would be aiming to deliver about 1t to the surface (not 'several tonnes'). The papers from AMES suggest an entry mass of about 7t, with 2t of that being the propellant burned in the last few seconds to reduce speed from Mach 2 to a soft landing. That leaves 5t to be landed, of which 4t is the capsule itself.
Now, that 4t figure for an empty Dragon equipped with landing gear and Super-Dracos is one that I find a little hard to digest. Bear in mind the far smaller Soyuz capsule, which has no large liquid fuelled engines or landing legs etc, is 3t. The Super Draco thrusters are going to have to pretty special indeed (i.e. have exceptionally high thrust:weight).
Not saying that this cannot work, obviously SpaceX and AMES think it can, but I think we should be aware of the margins that the system has.

Entry mass is proportional to the amount of drag that the vehicle can generate. A dedicated Mars lander would use the full 4.6m payload capacity of the FH, allowing, in theory, up to 60% greater entry mass than Red Dragon (i.e. over 11t). In addition, a dedicated platform could offer wider scope for different payloads, and could probably offer some mass savings by not carrying unnecessary hardware all the way to the surface.

I'm not saying that Red Dragon isn't a cool proposal- just I think some people are pinning too many hopes on it.
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Mongo
post Sep 17 2012, 09:30 PM
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Acording to SpaceX, the dry mass of a Dragon is 3,180 kg (albeit without landing structure).

The landed mass according to this proposal for Red Dragon EDL is stated as 5,180 kg

5,180 kg minus 3,180 kg is 2,000 kg

The "1,000 kg" figure being thrown about is a conservative estimate of landed payload, with a considerable safety margin. Depending on reentry trajectory and altitude of the surface, it can go higher (perhaps considerably higher, as seen in the above report).
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Kaputnik
post Sep 17 2012, 11:29 PM
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A 3180kg Dragon does not have, as far as I am aware, the Super-Draco engines included in that mass.

No data has been released on the mass of these engines. However, we do know that they will provide an a total axial thrust of 120,000lb; given that they are canted at an angle of at least 35 degrees, and probably more, the actual thrust produced must be in the region of 150,000lb or higher. A generous figure for thrust:weight ratio is about 50:1 (IMHO) which gives an engine mass of 1363kg, plus tank mass. The engine mass could easily be greater than this if they are canted at a steeper angle and/or if the T:W is lower. Admittedly the mass could be lower as well, but, again IMHO, not by much.

As you say, the landing gear and its deployment system also has to be accounted for.

If SpaceX have managed to squeeze the engines, tanks, and landing gear into a capsule the same weight as a Soyuz (which has none of those things), yet at the same time made it twice as big.... then I take my hat off to them!
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Posts in this topic
- Paolo   Red Dragon   Aug 7 2011, 09:46 AM
- - AndyG   ...and 1.2, and 1.3! I think the best thing w...   Aug 7 2011, 11:26 AM
- - pospa   Since payload capacity of Red Dragon to Mars surfa...   Aug 7 2011, 12:16 PM
|- - ugordan   QUOTE (pospa @ Aug 7 2011, 02:16 PM) Sinc...   Aug 7 2011, 03:37 PM
|- - djellison   QUOTE (ugordan @ Aug 7 2011, 08:37 AM) A ...   Aug 8 2011, 01:24 AM
|- - Jim from NSF.com   Full inline quote removed - ADMIN No, the capsul...   Aug 8 2011, 02:27 AM
- - Greg Hullender   Treating Dragon strictly as an unmanned vehicle, i...   Aug 8 2011, 12:07 AM
|- - ElkGroveDan   My recollection from the earliest days of SpaceX h...   Aug 8 2011, 12:48 AM
- - ElkGroveDan   The Viking landers and MSL wouldn't fit in it ...   Aug 8 2011, 03:20 AM
- - djellison   QUOTE (Jim from NSF.com @ Aug 7 2011, 06...   Aug 8 2011, 03:20 AM
|- - Jim from NSF.com   QUOTE (djellison @ Aug 7 2011, 11:20 PM) ...   Aug 8 2011, 05:37 PM
|- - djellison   QUOTE (Jim from NSF.com @ Aug 8 2011, 09...   Aug 8 2011, 05:55 PM
|- - Jim from NSF.com   QUOTE (djellison @ Aug 8 2011, 01:55 PM) ...   Aug 8 2011, 08:16 PM
|- - djellison   QUOTE (Jim from NSF.com @ Aug 8 2011, 01...   Aug 8 2011, 08:35 PM
|- - Jim from NSF.com   QUOTE (djellison @ Aug 8 2011, 04:35 PM) ...   Aug 9 2011, 12:12 AM
|- - djellison   QUOTE (Jim from NSF.com @ Aug 8 2011, 05...   Aug 9 2011, 01:21 AM
|- - Jim from NSF.com   QUOTE (djellison @ Aug 8 2011, 08:21 PM) ...   Aug 12 2011, 12:41 AM
- - ZLD   Just out of curiosity, are there any obvious appli...   Aug 8 2011, 11:44 PM
|- - ugordan   QUOTE (ZLD @ Aug 9 2011, 01:44 AM) Also, ...   Aug 9 2011, 08:07 AM
- - nprev   If I'm not mistaken, I think that Red Dragon w...   Aug 8 2011, 11:51 PM
- - ZLD   QUOTE a couple of intermediate-sized rovers poppin...   Aug 9 2011, 12:06 AM
- - nprev   Jim, one point you have to remember about Red Drag...   Aug 9 2011, 12:48 AM
- - ZLD   QUOTE Driving rovers out the hatch is ludicrous, t...   Aug 9 2011, 01:06 AM
|- - centsworth_II   QUOTE (ZLD @ Aug 8 2011, 08:06 PM) ...som...   Aug 9 2011, 01:24 AM
- - nprev   Yep; many ways to skin that cat. You could even pu...   Aug 9 2011, 01:30 AM
|- - centsworth_II   QUOTE (nprev @ Aug 8 2011, 09:30 PM) ...Y...   Aug 9 2011, 01:36 AM
- - ZLD   Kind of like the tumbleweed idea thats been floate...   Aug 9 2011, 01:49 AM
|- - centsworth_II   QUOTE (ZLD @ Aug 8 2011, 08:49 PM) Kind o...   Aug 9 2011, 02:30 AM
- - DDAVIS   I would have cameras at least pointing out the win...   Aug 9 2011, 04:12 AM
- - djellison   You sound like Mike Wolff. In a good way. Top hat...   Aug 9 2011, 05:56 AM
|- - ElkGroveDan   Think of the weather station and seismometer you c...   Aug 9 2011, 06:00 AM
- - Astro0   Of course thinking outside the box or in this case...   Aug 9 2011, 07:39 AM
|- - Jim from NSF.com   QUOTE (Astro0 @ Aug 9 2011, 02:39 AM) OfJ...   Aug 12 2011, 12:33 AM
- - pospa   We are talking about Discovery category mission, r...   Aug 9 2011, 11:09 AM
|- - algorimancer   QUOTE (pospa @ Aug 9 2011, 05:09 AM) ...w...   Aug 9 2011, 12:57 PM
- - Drkskywxlt   Although I think this proposed proposal (how's...   Aug 9 2011, 12:51 PM
- - Mongo   For a Mars mission, there are two kinds of distanc...   Aug 9 2011, 05:01 PM
- - djellison   It's not out of the question that the vehicle ...   Aug 9 2011, 05:18 PM
- - Mongo   I had a wild idea, does anybody know if it is tech...   Aug 9 2011, 05:37 PM
|- - Mongo   From Emily's Planetary Society blog: QUOTE Mo...   Mar 16 2012, 01:04 AM
|- - Gsnorgathon   Good call, Mongo! Now, do you have some sugges...   Mar 16 2012, 06:26 AM
- - ZLD   Drilling through the bottom is a possibility, as i...   Aug 9 2011, 05:53 PM
- - Fran Ontanaya   It may be robust enough to survive a winter buried...   Aug 9 2011, 07:05 PM
- - lyford   Delurking in this thread just long enough to say H...   Aug 9 2011, 11:30 PM
- - MarsInMyLifetime   I'm new to UMSF, but a long-time advocate of r...   Aug 10 2011, 06:08 AM
|- - ugordan   QUOTE (MarsInMyLifetime @ Aug 10 2011, 08...   Aug 10 2011, 08:06 AM
|- - MarsInMyLifetime   QUOTE (ugordan @ Aug 10 2011, 02:06 AM) ....   Aug 10 2011, 04:08 PM
- - Fran Ontanaya   Maybe it could orbit Mars, mapping with a big gamm...   Aug 12 2011, 02:20 AM
- - ZLD   QUOTE (Jim from NSF.com @ Aug 11 2011, 06...   Aug 12 2011, 02:43 AM
|- - ElkGroveDan   QUOTE (ZLD @ Aug 11 2011, 07:43 PM) Jim, ...   Aug 12 2011, 05:56 AM
- - Greg Hullender   I hate to appear to agree with Jim, but I'm ju...   Aug 12 2011, 03:33 AM
- - stevesliva   On the other hand, NASA also has a history of desi...   Aug 12 2011, 05:45 AM
- - nprev   "A solar-powered rover lasting for over seven...   Aug 12 2011, 07:15 AM
- - djellison   Jim has been asked, in private, and publicly, by U...   Aug 12 2011, 08:00 AM
- - SteveM   "The idea is like grass, It craves light, lik...   Aug 12 2011, 04:48 PM
- - Drkskywxlt   I think people have posted several ideas of how SO...   Aug 12 2011, 05:08 PM
- - Astro0   "...but I don't think any of that science...   Aug 13 2011, 06:32 AM
|- - Drkskywxlt   QUOTE (Astro0 @ Aug 13 2011, 01:32 AM) Oh...   Aug 15 2011, 12:50 PM
- - Oersted   I imagine a snake crawling out of the hatch... ht...   Aug 13 2011, 08:00 PM
- - Syrinx   It might be worth simply emailing Elon Musk and as...   Aug 18 2011, 08:42 PM
- - Paolo   there is an article on Red Dragon on this week...   Nov 9 2011, 07:45 PM
- - Drkskywxlt   Usually teams that are proposing Discovery or NF m...   Nov 9 2011, 08:46 PM
|- - djellison   QUOTE (Drkskywxlt @ Nov 9 2011, 12:46 PM)...   Nov 9 2011, 09:50 PM
|- - vjkane   ADMIN - Full inline quote removed. You should know...   Nov 9 2011, 10:25 PM
- - Phil Stooke   True! But nobody else is likely to steal this...   Nov 9 2011, 09:26 PM
- - djellison   And someone else could also propose a Red Dragon p...   Nov 9 2011, 10:36 PM
- - Drkskywxlt   Dragon is a platform, Red Dragon is a specific mis...   Nov 10 2011, 11:26 AM
|- - djellison   QUOTE (Drkskywxlt @ Nov 10 2011, 03:26 AM...   Nov 10 2011, 02:45 PM
- - nprev   Well, let's redirect by all means, then! ...   Nov 10 2011, 03:46 PM
|- - vjkane   QUOTE (nprev @ Nov 10 2011, 07:46 AM) Any...   Nov 10 2011, 03:54 PM
- - Drkskywxlt   I would definitely expect foreign instruments (or ...   Nov 10 2011, 03:59 PM
- - nprev   Hmm. All that terrific payload capacity... What d...   Nov 10 2011, 04:08 PM
- - Paolo   this presentation of Red Dragon has been posted on...   Dec 13 2011, 07:04 PM
- - Kaputnik   It's been interesting to figure out how Red Dr...   Sep 16 2012, 03:03 PM
- - Mongo   That's the big question -- whether it would be...   Sep 17 2012, 05:17 PM
|- - Kaputnik   A 'nearly stock' Dragon would be aiming to...   Sep 17 2012, 08:39 PM
|- - Mongo   Acording to SpaceX, the dry mass of a Dragon is 3,...   Sep 17 2012, 09:30 PM
|- - Kaputnik   A 3180kg Dragon does not have, as far as I am awar...   Sep 17 2012, 11:29 PM
- - dtolman   A few days ago Space.com posted a speculative arti...   Sep 17 2015, 12:45 AM
- - sittingduck   I have a question concerning the CGI used to showc...   Sep 18 2015, 09:38 AM
- - eoincampbell   Just beyond Dingo Gap sol 528   Sep 18 2015, 03:33 PM
- - sittingduck   Thanks eoincampbell! By my reckoning that p...   Sep 18 2015, 04:22 PM
- - anticitizen2   I am hearing that Red Dragon is more likely to get...   Jan 4 2016, 04:40 AM
|- - stevesliva   QUOTE (anticitizen2 @ Jan 4 2016, 12:40 A...   Jan 4 2016, 04:49 AM
|- - mcaplinger   QUOTE (anticitizen2 @ Jan 3 2016, 08:40 P...   Jan 4 2016, 05:17 AM
|- - vjkane   QUOTE (anticitizen2 @ Jan 3 2016, 08:40 P...   Jan 4 2016, 01:13 PM
- - Phil Stooke   Phil   Apr 27 2016, 04:12 PM
- - Seryddwr   We're gonna need more wheels... Serio...   Apr 27 2016, 05:11 PM
|- - dtolman   The article at Gizmodo has more details than the t...   Apr 27 2016, 07:58 PM
- - Explorer1   Things are starting to heat up! (no pun intend...   Apr 27 2016, 10:15 PM
- - elakdawalla   Red Dragon could enable some exciting future robot...   Apr 27 2016, 10:53 PM
- - acastillo   I suspect, and would encourage NASA to propose and...   Apr 27 2016, 11:10 PM
- - Stratespace   In this techno-oriented mission, I imagine more pa...   Apr 27 2016, 11:17 PM
- - nprev   I would expect this initial mission to be almost p...   Apr 28 2016, 02:06 AM
|- - dtolman   NASA's statement on their partnership with Spa...   Apr 28 2016, 03:01 AM
- - nprev   If they're smart--and there's no doubt tha...   Apr 28 2016, 03:40 AM
- - climber   When exactly will be 2018 launch window?   Apr 28 2016, 05:09 AM
- - Paolo   launch window should be around May +/- one month   Apr 28 2016, 05:11 AM
- - tanjent   This is an issue that has arisen recently in Schia...   Apr 28 2016, 05:28 AM
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