Space Storable Propellants

[holmec]

>At that point though, the main engine was useless, correct? Hence, the system would not qualify as "storable."<<br /><br />Remember that the lander had two engines, a descent and an ascent. So I assume your talking about the descent engine but the ascent as far as I know was not used in that mission. Or is it the case that the helium in the ascent engine evaporated? <br /><br />Anyway when talking about storability you want to talk about the period of time your storing for. And the lander and SM both had to have some storability capability, at least for a week or so. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[willpittenger]

It was the descent engine. Shuttle Guy has already stated that the helium was pressurized -- not liquid. It would not evaporate. I think we need enough storability to last through the lunar night (may be even months) and be capable of launching on a moments notice -- night or day. That is a wide range of temperatures and it needs to last a long time. <br /><br />That extreme storability requirement was why I listed solid fuel as something we needed. <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>

 

[propforce]

Solid propellant may not be as storable as you'd imagine. Under extreme temperatures, it could crack or flake off as well. <br /> <div class="Discussion_UserSignature"> </div>

 

[j05h]

<i>>Solid propellant may not be as storable as you'd imagine. Under extreme temperatures, it could crack or flake off as well. </i><br /><br />That might be another point in favor of paraffin hybrids, especially if you had a multiphase material for the oxidizer. The wax isn't going to expand when solid (unlike H20) and you just need a storable gas to go with it. <br /><br />My favorite "moon" rocket has to be aluminum-LOX. Industrial, abundant and doesn't waste precious hydrogen.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[vulture2]

Aluminum-Lox hybrids have apparently been tested with some sucess on a small scale. However fabrication of aluminum on the moon would require considerable infrastructure. <br /><br />For spacecraft fueled on or from Earth, particularly manned or reusable vehicles, propane and nitrous oxide seems an attractive combination, with LOX/propane perhaps having an advantage in short missions where boiloff is not a problem. <br />