SpaceX Jan Update Posted: Plan F-1 Class Motor!

[tap_sa]

<font color="yellow">"But, as you said, that wasn't a rendezvous - though it fooled the West for a long time."</font><br /><br />Depends on the definition of rendezvous. According to Webster:<br /><br /><i>3 : the process of bringing two spacecraft together</i><br /><br />In early vostok flights this process was accomplished solely by booster. Later spacecrafts performed orbital adjustments after reaching LEO. Gemini 6 reached Gemini 7 in about six hours after launch, again from astronautix.com: <br /><br /><i> The coelliptic maneuver was performed at third apogee, 3 hours 47 minutes after launch. The terminal phase initiation maneuver was performed an hour and a half later. Two midcourse corrections preceded final braking maneuvers at 5 hours 50 minutes into the flight. Rendezvous was technically accomplished and stationkeeping began some 6 minutes later when the two spacecraft were about 120 feet apart and their relative motion had stopped.</i><br /><br />Note that rendezvous doesn't necessarily mean <i>docking</i> which is a natural requirement for ISS/ASP flights.

 

[najab]

><i>3: the process of bringing two spacecraft together</i><p>Actually, this definition makes my point - they weren't <i>brought</i> together at all. The launches were timed so that the two spacecraft passed each other <b>once</b> - they didn't stationkeep relative to each other and never came close again. This was more an intercept, rendezvous is when you make the orbit of the two vehicles the same.<p>><i>Note that rendezvous doesn't necessarily mean docking which is a natural requirement for ISS/ASP flights.</i><p>Ah, but docking means rendezvous - when two spacecraft have <b>truly</b> rendezvoused, they can dock (assuming they have compatible docking mechanisms) - the Vostok missions <b>could not have docked</b> even if they did have the means to so do because their orbits were not the same.</p></p></p>

 

[no_way]

"when two spacecraft have truly rendezvoused, they can dock (assuming they have compatible docking mechanisms) - the Vostok missions could not have docked even if they did have the means to so do because their orbits were not the same. "<br /><br />Or to put it simply: they have<br />-stationkeeping when the relative speed is zero<br />-docking when both the relative speed is zero and distance is zero<br />

 

[najab]

<i>-stationkeeping when the relative speed is zero<br />-docking when both the relative speed is zero and distance is zero</i><p>And a big problem when the distance is zero and the relative speed is not!!! <img src="/images/icons/shocked.gif" /></p>

 

[mrmorris]

<font color="yellow">"Good work on the GX3, but I am not buying the numbers ...yet. "</font><br /><br />I was working on something else and ran across a recent set of my G-X3 mass figures and figured I'd add them here. You need not purchase them -- but I would hope they will make you go 'Hmmm'. The vast majority of both the mass reductions and additions are from official Gemini docs or specifications found in documentation. Where I haven't got documented figures, I tried to be conservatively low on reductions and conservatively high on additions.<br /><br />Gemini Mission 3: 3,574 kg (closest mission to G-X3. Short duration and battery powered -- easier to pull a discrete power system mass than Fuel-Cell missions)<br /><br />Front RCS: -133 kg<br />Suit ECS: -80 kg<br />RM Main batteries: -31 kg <br />RM Squib batteries: -11 kg<br />EM batteries: -321 kg<br />Cabin Water tank: -8 kg<br />EM Water Tank: -90 kg<br />Ejection Seat Catapults: -20 kg<br />Biomedical equipment and diagnostics: -10 kg<br />Deleted R&D Instrumentation: -33 kg<br />Separation pyrotechnics: -10 kg<br />Wire Guillotines: -5 kg<br />Modern Heat Shield: -72 kg<br />Modern Electronics: -270 kg<br />Total weight subtractions: -1,094 kg<br /><br /><br />Li-Ion Batteries (8850 Whr): +65 kg<br />4 Additional retro Rockets: +165 kg<br />APAS (docking system): +286 kg<br />Apollo Parachutes: +100 kg<br />3 additional people: +300 kg<br />3 additional crew couches: +300 kg<br />Cabin ECS: +200 kg<br />Total weight additions: +1,416 kg<br /><br />Approx End Weight -- Gemini-X3: 3,896 kg<br /><br /><br />Considering that this leaves ~1,500-2,000 kg of spare lift mass on the Falcon V specs... I'd really have to be missing a heckuva lot for this not to be feasible.

 

[severian]

There's one other thing to consider here, which only helps the numbers.<br /><br />SpaceX has two planned improvements to the Falcon V before they build anything based on this new F-1 class rocket - firstly they intend to put a RL-10 LOX/LH2 upper stage on the Falcon V (although the last time they mentioned this change was before they went with using the Merlin instead, so this _might_ no happen), and also they intend to develop a Merlin 2 engine, which I assume will be placed into a modified Falcon V. Since they haven't released numbers, it's hard to say what kind of a payload increase this will give them, but I would expect it to be over 10,000 kg to LEO.<br /><br />And to the person who said that an F-1 class engine would enable to compete with with the Atlas V and Delta IV - that's something of an understatement. Only four rockets currently generate more than 1,500,000 lb's of thrust at liftoff, which is the Titan IV, the Delta IV Heavy, the Ariane 5, and the Space Shuttle. Even a single engined version of a rocket based around that would be a very serious machine.

 

[mikejz]

I believe that that the Merlin 2 is for the Falcon V and is represented in its current specs. The first few Falcon V flights will be with Merlin 1s and will not lift as much. <br /><br />Given the 3 Million pound test stand I would say that the SpaceX might be thinking along a few ways.<br /><br />1) A 2.5-3 Million Pound thrust engine for a single engine first stage. A Falcon V based 2nd stage. <br />(Not sure about this one)<br /><br />2) A 1.5 Million Pound thurst engine with single and dual engine models made. 2-3 Merlins will be used for the single engine upper stage, a Falcon V config for the 2 engine.<br /><br />I really wounder what opporunity Musk sees in this class of launcher? I see a few options.<br /><br />1) Thinks that NASA really would like a HHLV but for political reasons has not stated such. <br /><br />2) Private companies have approched with confidential projects (IE Space Hotels)<br /><br />3) Thinks the Delta 4H, Atlas 5 are in a market that is set to grow, or that he can get DOD work.<br /><br />4) Intresting internal project. For example, launching com satellites unfueled and establishing a fueling station supplied by BDBs.

 

[dschmelzer]

Rather, the Merlin 1A is the original engine. The Merlin 1B is the basis for the upgraded Falcon V numbers on SpaceX's site. No numbers or configuration have been released on the Merlin 2 or the F-1 class engine other than to say that the F-1 class engine will have more than 1.5 million lbs. of thrust.<br /><br />FYI: I think the 3 million lb test stand was inherited from Beal Aerospace.<br /><br />The business that hasn't been matched with a launcher is Bigelow's Nautilus module, which is said to weigh 50,000 lbs (23,000 kg). As you say, there are only a small number of launchers capable of this, and most are very expensive.

 

[mikejz]

Thanks for the correction. I thought it was Beal Aerospace too--However Beal's launcher was going to be based on a 4.3 Million Lbs Engine. I wounder why they only built a table rated for 3? <br /><br />

 

[dschmelzer]

My information from somebody who worked at Beal was that it was a 3 million lb. thrust vehicle, although I guess specs can change from time to time, as they have with SpaceX. <br /><br />In any event, if Bigelow is going to launch the first Nautilus in the 2008 - 2010 timeframe as planned, then we'll probably know soon what vehicle with which he is pairing it.

 

[nacnud]

I thought that the Proton booster was going to be used, but I can't remember where I heard that.

 

[spacester]

How big a hotel indeed? Pretty exciting stuff, and what a great thread!<br /><br />On-orbit, in-plane maneuvers within LEO are *not* propellant expensive. It just doesn't take that much detaV to get around once you're up there. LEO really <b>is</b> halfway to anywhere in the solar system, and elsewhere in LEO is a trip down the block.<br /><br />The perception is often different because virtually all of our experience has been with vehicles with a razor-thin margin for propellant mass. As mrmorris points out very well, if you simply design a vehicle which doesn't push its booster to the limit, you have plenty of margin to get around in LEO. (Don't *make me* post a bunch of equations lol.) <br /><br />Simply include a lot of orbital maneuvering capability in the vehicle's performance specifications. Build the tanks bigger, fill them up, get it going really fast with the booster, and there you are! Get a filling station going, and hey presto orbital maneuvering becomes commonplace, which is a good thing, right? <img src="/images/icons/laugh.gif" /> <div class="Discussion_UserSignature"> </div>

 

[tap_sa]

<font color="yellow">"Considering that this leaves ~1,500-2,000 kg of spare lift mass on the Falcon V specs"</font><br /><br />Any idea what the payload fairing of Falcon V weighs? Not really much need for that with G-3X so there's another weight saving.

 

[mrmorris]

<font color="yellow">"... so there's another weight saving. "</font><br /><br />I'm going to answer this in my G-X3 thread. I'd like to keep the G-X3 posts together as much as possible.