More on Orion to NEOs

[JonClarke]

There are a couple of abstracts at the forthcoming LPSC about Orion missions to NEOs that people might find interesting.<br /><br />Enjoy!<br /><br />http://www.lpi.usra.edu/meetings/lpsc2007/pdf/2292.pdf<br /><br />http://www.lpi.usra.edu/meetings/lpsc2007/pdf/2083.pdf<br /> <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[willpittenger]

120 days in a tiny capsule vernable to radiation? No thanks. I assume we are talking about the same crew complement that would go to the Moon. It would be crowded. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[mattblack]

There'll be a "Mission Module" or "Habitat Module" for the crew to live in en-route to-and-fro to the asteroid: such a thing will be necessary to manned Mars missions. <div class="Discussion_UserSignature"> <p> </p><p>One Percent of Federal Funding For Space: America <strong><em><u>CAN</u></em></strong> Afford it!!  LEO is a <strong><em>Prison</em></strong> -- It's time for a <em><strong>JAILBREAK</strong></em>!!</p> </div>

 

[Boris_Badenov]

The first article says the crew complement would be 2 or 3. My guess would be three, that way they could have 24 hour shift coverage if necessary. If a Habitation module is indeed included there will be plenty of area to get away from each other. <div class="Discussion_UserSignature"> <font color="#993300"><span class="body"><font size="2" color="#3366ff"><div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div></font></span></font> </div>

 

[JonClarke]

The rule of thumb for 6 month missions is 15 cubic m of pressurised volume per person as an absolute minimum, with 30 cubic m per person as the useful minimum.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[Boris_Badenov]

The only thing I can say about the second article is, WOW!!! It tells us about the goals of an NEO mission & describes the capabilities of the hardware that could be used to complete said mission, but it doesn't give us a very clear idea of how the ship would be configured. <br /> Another concept not described in the article is the re usability of the hardware involved. Will everything be tossed except the Orion capsule? If this is the case, I'll have to withdraw my support.<br /> The initial expense will be much greater for fully reusable components, but the savings will be greater in the end. <div class="Discussion_UserSignature"> <font color="#993300"><span class="body"><font size="2" color="#3366ff"><div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div></font></span></font> </div>

 

[holmec]

Fantastic...thanks Jon. <img src="/images/icons/laugh.gif" /> <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[JonClarke]

That is no different to lunar misions where the only thing that can be always reused is the reentry module.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[holmec]

That's great! Get the VSE going in the right direction with congressional support and put manned space program in with planetary defense research.<br /><br />Outstanding. <br /><br />And proposed Delta IV to assist to boot. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[gunsandrockets]

"The rule of thumb for 6 month missions is 15 cubic m of pressurised volume per person as an absolute minimum, with 30 cubic m per person as the useful minimum."<br /><br />Very interesting. <br /><br />Is there a scientific basis for that rule of thumb? Or is it just an engineering WAG?

 

[gunsandrockets]

The 2292.pdf link downloads a file without any content.

 

[Boris_Badenov]

<font color="yellow"> That is no different to lunar misions where the only thing that can be always reused is the reentry module. <br /> </font><br /><br /> A big chunk of the ship that goes to the Moon is left on the Moon for future use, so that's not a particularly good example. If 75 to 90 percent of the ship is thrown away at the end of the NEO rendezvous mission, that is not a good way to visit asteroids. It's just too expensive. We need a ship that has 90 percent re usability, not 10 percent. <div class="Discussion_UserSignature"> <font color="#993300"><span class="body"><font size="2" color="#3366ff"><div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div></font></span></font> </div>

 

[solarspot]

The cost of the individual pieces of hardware is neglegable... the cost of getting it into orbit is less than half the cost of any mission... the big cost of it is developing the modules, and that only happens once ever. Reusability is overrated unless you're flying thousands of times like aircraft do. Why the space shuttle is so expensive

 

[Boris_Badenov]

<font color="yellow"> Why the space shuttle is so expensive </font><br /><br /> The Space Shuttle is so expensive because of the army that works with it. Some 15,000 IIRC.<br /><br /><font color="yellow"> Re usability is overrated unless you're flying thousands of times like aircraft do. </font><br /><br /> That's entirely correct. Build the ship in orbit. Refuel it in orbit. Power it with even the earliest of NERVA engines design & you have a 100 percent reusable ship & you can plan missions around your ship, rather than plan the ship to be mission specific. <div class="Discussion_UserSignature"> <font color="#993300"><span class="body"><font size="2" color="#3366ff"><div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div></font></span></font> </div>

 

[JonClarke]

It's a semi-quantitative WAG, I would say, based on actual historical spacecraft experience. Various expressions of this relationship can be found in Larson and Pranke (eds.) "Human Spaceflight: Mission Analysis and Design" (McGraw-Hill 1999). <br /><br />The clearest is Figure 6-2 which gives the optimal, performance limit and tolerance limits for habital volumes from missions ranging in duration from 0 to 12 months. The curves are essentially flat after 6 months. The pressurised volume limits for these are 20, 10 and 5 cubic m respectively, which have to multiplied by 3 to give the actual pressurised volume (allowing for storage, systems, fittings, etc.), thus giving60, 30 and 14 cubic m.<br /><br />It's a great source of actual data and empirical rules of thumb. It covers almost every aspect of manned spaceflight to LEO, the Moon and Mars imaginable. Well worth reading and having. It's a great way of discovering whether or not designers of future craft are realistic or optimistic or pessimistic in their designs. <br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[JonClarke]

"A big chunk of the ship that goes to the Moon is left on the Moon for future use, so that's not a particularly good example. If 75 to 90 percent of the ship is thrown away at the end of the NEO rendezvous mission, that is not a good way to visit asteroids. It's just too expensive. We need a ship that has 90 percent re usability, not 10 percent."<br /><br />Unless the crews return to the same location each time nothing left on the Moon will be reused. Even if they do little of the initial versions of the LSAM will be reusable, although I would imagine that specific equipment items such as rovers and tools might be.<br /><br />Reusability in and of it self is of no value, it is only valuable if it makes missions simper and cheaper. Experience to date indicates that it does not, at our current level of space technology, and that of the immediate future, for missions to LEO and beyond.<br /><br />Besides, think through what resuability in an asteroid mission actually means. An Orion mission to an asteroid would need an Earth departure stage , a reentry module, a service module, and a mission module.<br /><br />A resuable EDS would mean giving it sufficient dV to be able to return to Earth and a means of servicing and resupplying it with tens of tonnes of propellant in LEO..<br /><br />A resuable service module must carry sufficient propellant to enter LEO at the end of a mission and the ability to be refurbished and resupplied.<br /><br />This means that the reentry module must be capable of deorbiting without the servicmodule, which means extra propellants and engines.<br /><br />A resuable misison module would have to be braked into LEO and then be refurbished and resupplied.<br /><br />All this means a much larger and more complex mission and supporting missions and infrastructure. In other words more expensive than new spacecraft modules each time.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[JonClarke]

"The Space Shuttle is so expensive because of the army that works with it. Some 15,000 IIRC. "<br /><br />The reason the Shuttle needs so many people is because it is reusable, which means reverification, refurbishment and resupply after each mission.<br /><br />"Build the ship in orbit. Refuel it in orbit. Power it with even the earliest of NERVA engines design & you have a 100 percent reusable ship & you can plan missions around your ship, rather than plan the ship to be mission specific."<br /><br />That means building your EDS stage to much more exacting specifications if it is going to be used many times. <br /><br />It means greatly enlarging it so that it has enough propellant to come home again. <br /><br />You would need develop a large tanker capable of carrying up to 100 tonnes of cryogenic propellant and transfer in in zero gravity so that it can be refuelled between missions. That is a whole additional HLV mission. <br /><br />You also need the ability to inspect and if necessary repair your engines (remotely if it is NERVA). That is a separate manned or unmanned mission involving an extensive program of EVAs or teleoperated repairs<br /><br />In other words a much larger and more complex EDS, two whole new vehciles (tanker and servcing spacecraft), two additional launches and orbital renezvous. How is this cheaper than continued use of simple disposable stage that already exists?<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[willpittenger]

A Orion capsule would be a problem on Mars. It can make only one descent. So you need a second lander capable of reentry (at least in the Martian atmosphere) and at least one relaunch back into space <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[JonClarke]

I don't know anyone who has suggested use of an Orion capsule to land on or launch from Mars.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[mattblack]

I said they need a Hab module for the EN-ROUTE voyage to Mars: The lander would be attached to the other end. The total habitable volume for the combined Orion, Hab & Lander for the outbound mission would be less than 4,000 cubic ft (90-cubic meters, not including the boxes/containers of consumables) if they don't use an inflatable Hab. This is about the same volume that a crew of 7 has on a Shuttle flight that includes a Double-SpaceHab or the old Spacelab module.<br /><br />When I interviewed Shannon Lucid 10 years ago, she said that one night when the crew was having dinner on STS-58, one of them commented on how they wished Columbia had enough fuel to burn out of Earth Orbit and head for Mars. Another crewmember said; "But wouldn't we all go a bit 'koo-koo' in this small setting?" The others, Lucid included, said no; the Mid-Deck and Spacelab would be room enough, as long as the toilet kept working!!<br /><br />So they all thought that about 3500 cubic ft would be adequate, or nearly so. A similar volume would be even better if the crew were reduced from 6 to 5 or even 4.<br /><br />Orion -- 380 cubic ft.<br /><br />Mission/Hab module -- 1500 cubic ft(?): Nett Volume, before using up consumables and their collapsible, crushable packaging. Module approx. equivalent to I.S.S. MPLM dimensions.<br /><br />Mars Hab/Lander -- 2000 cubic ft(?). About twice that of notional LSAM design.<br /><br />Volume per crewmember (x6) = 650 cubic-ft (18 cubic-meters per crew). <div class="Discussion_UserSignature"> <p> </p><p>One Percent of Federal Funding For Space: America <strong><em><u>CAN</u></em></strong> Afford it!!  LEO is a <strong><em>Prison</em></strong> -- It's time for a <em><strong>JAILBREAK</strong></em>!!</p> </div>

 

[JonClarke]

That is an interesting comment from one of the most experienced NASA astronauts with 222 days in space over five missions. It is worth analysing.<br /><br />She said that 3,500 cubic feet was "adequate", this is near enough 100 cubic metres in the real world. That is 15 cubic m per crew member for a 7 man mission. Fifteen cubic m has been identified as the tolerable limit for a 6 month mission by Larson and Pranke.<br /><br />On a Mars mission you would need more volume than this to accommodate items not needed on a shuttle mission. A much more comprehensive workshob, a fully equipped sick bay, individual cabins, a second airlock, storage for 400 days of spares and consumables, more exercise equipment, a semi-closed life support system, etc., this would give you plenty of room.<br /><br />With your hypothetical case I would suggest that a Mars hab/lander with 2000 cubic feet (57 cubic m) would provide the tolerable limit for missions of up to 30 days. For a dedicated lander mission crew of three, 57 cubic m would allow surface stays of up to two months at the performance limit. So it looks like you are assuming a short stay Mars mission in your case. <br /><br />if you wanted a long stay Mars mission (18 months) you would want a bigger lander, with 30 and 50 cubic metres per person. That means an ideal pressurised volume for a crew of 6 of 360 cubic metres. <br /><br />The Mars Society presently operates two simulated Mars research stations, one in Utah and one on Devon island. These have internal volumes of ~400 cubic metres. Speaking from experience, this is very roomy.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[mattblack]

Oh sure! You're right. I based my 2000 cubic-ft Lander volume on the basic assumption that a Mars Lander may have a habitable volume that is sized to be the maximum an LSAM-based chassis could fit on top. Also, its always been interesting to me how ingenious the engineers have always been incorporating fold-away and collapsible exercise machines, tables and cabinetry into the Shuttle Mid-decks, Spacelab modules, Mir and ISS layouts. Even roomy Skylab used 'tables' and workstations for multiple purposes.<br /><br />You know, I used to have a tiny bedroom in one place I lived that was hardly big enough for one single bed, a small table and a bookcase. Yet this room incorporated my first bulky PC, my TV and video equipment and I had a small closet. This bedroom was my library, communications center, gym, audio-visual theater & workshop. I had gear on and up the wall, in cupboards, fold-out shelves and under the tiny desk and bed.<br /><br />I loved that little room and I utilised it to the full. If you imagine that concept x5 or x6 with added rooms of 1x common toilet and a combined showerbox/laundry/wash station and 1x Wardroom/Lounge/Kitchen; you could just about do it -- as long as at least one room in the Hab module was relatively spacious, I'd say the Wardroom.<br /><br />And of course, for the Martian surface, you've probably seen the Nasa DRM-1 & 3 concepts for co-joined modules and/or attached Bigelow-style inflatables. <div class="Discussion_UserSignature"> <p> </p><p>One Percent of Federal Funding For Space: America <strong><em><u>CAN</u></em></strong> Afford it!!  LEO is a <strong><em>Prison</em></strong> -- It's time for a <em><strong>JAILBREAK</strong></em>!!</p> </div>

 

[JonClarke]

Your estimate may give an idea as to what sort of maximum duration mission could be expected from a LSAM.<br /><br />It certainly is remarkable how much can be fitted into a confined space with clever design. Submarines, aircraft, campervans, and boats all suggest useful approaches for compact living spaces in spacecraft. I think you are right too in the need for at least some large spaces, preferably where the crew can reflax. Ideally this woulod have a large window for looking out as well.<br /><br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[j05h]

Jon- Many of your criticisms are solved/alleviated by basing from L1 instead of LEO. It takes more to get to L1 from Earth but is easier to access Luna and interplanetary space. It's also easier to get to on the return since you don't need to descend so far into Earth's gravity well. Basing at L1 means not having to carry a capsule out to the asteroid, since you'll be returning to "docks" that have your L1-Earth transport waiting. <br /><br />Tankers don't need to be as large as suggested, either. 100 tons of fuel in a single shot is horribly expensive - better to split it up and fly on cheaper/smaller vehicles. <br /><br />L1 would allow your NEO mission to use more lenient aerocapture (into HEEO, then circularize to L1) than diving straight into LEO or worse yet, aerobraking to Earth's surface. A Parom-style tug (but based @ L1) leverages this kind of architecture, as does ISRU from any source. An option for returning un-crewed stages (EDS alone) would be electrodynamic tethers to adjust orbits. It's already going to have solar panels, the wire isn't that heavy.<br /><br />The important factor is splitting up Earth-L1 transport from the rest of the trip. <br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[JonClarke]

There are several issues with using L1 in this context.<br /><br />1) The Constellation architecture is not designed to use L1 for for other than parking. More extensive use of L1 requires development of more hardware and thus greater cost. <br /><br />2) There is little or no saving in propellant in going to NEOs or anywhere else via L1 if your propellant in sourced from earth. <br /><br />3) Whether you do it in LEO orL1 you still need to fly servicing missions. It takes more propellant to fly these to L1 than LEO. <br /><br />4) Splitting your propellant into smaller packages over more missions means that the probability of delays because of technical problems, docking failures, and launcher malfuctions. No good you uou are aiming for a tight launch window. Because smaller tankers are less efficient than large ones you also need more propellant overall. <br /><br />So what's the point of using L1? As far as I can see L1 only becomes attractive if you can make substantial amounts of propellant on the Moon. And that is much further down the track that the sort of missions being discussed in these abstracts.<br /><br />Jon<br /> <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>