Is Altair’s ascent stage now to use liquid methane?

by | Feb 11, 2009 | Seradata News | 1 comment

altair ldac2 ascent stage.JPG

credit: NASA / caption: this is the LDAC-2 ascent stage design, LDAC-3 will finish in March

It looks like the NASA Altair Lunar Lander’s ascent stage could use liquid methane (LCH4) instead of the baselined hypergolics as the space agency has just published a synposis that says: “NASA system trade studies have shown that LCH4 ascent stage propellant tank fluid venting can be eliminated on the lunar surface for the 210 day mission…”

But can the pressurant last for that seven month mission? That’s another issue but in a synopsis for a forthcoming request for propoals, which will kick off the procurement process to design, fabricate and install a low heat leak, tank-applied Multi-layer Insulation (MLI) system, it says that 60 layers will be needed for the LCH4 fuel

That and apparently loading at the Kennedy Space Center (KSC) launch pad the LCH4 tanks with “densified LCH4 at 165 oR” and starting with a tank ullege of approximately 15% will do the job; so now you know!

Here is a description of the densification process care of a NASA technical paper from 2005

Each densification production process uses a high-efficiency, subatmospheric boiling bath heat exchanger to cool the working fluid. A near triple-point hydrogen boiling bath is used to condition and subcool hydrogen to 27 R (15 K), and a nitrogen boiling bath is used to cool the liquid oxygen to 120 R (66.7 K). Multistage centrifugal compressors operating at cryogenic inlet conditions maintain the heat exchanger bath vapor pressure below 1 atm. The LO2 propellant densification unit shown in the photograph has a 30 lb/sec capacity, whereas the LH2 unit was designed to process 8 lb/sec of propellant.

To make sure this 60-layer MLI solution works NASA will test a “flight-representative, spherical LCH4 ascent stage propellant tank” as part of its Cryogenic Fluid Management (CFM) Project

An “inter-center team” from Ames Research Center, Glenn Research Center (GRC), KSC and Marshall Space Flight Center will carry this out at a GRC facilty that will be used to conduct experiments in “a simulated lunar thermal environment”

But there may still be problems with a LCH4c ascent stage. I wrote last year about pressurisation issues relating to landing aborts and excess pressure at the end of a 210-day mission. It would seem NASA is now more confident of the 210-day stay but what of the landing abort?

NASA has already test fired a LCH4 engine that is either a candidate for Altair’s ascent stage or will contribute to its propulsion system’s development

The slide below, which is from NASA’s December 2007 briefing to the US National Research Council about work done under the space agency’s Propulsion and Cryogenics Advanced Development programme shows the benefits of using methane over hypergolics 

click on the image below to see a larger version in the same browser window

PCAD Altair ascent LCH4.JPG

credit: NASA

About Seradata

Seradata produce the renowned SpaceTrak Launch & Satellite Database. Trusted by 100 of the world’s leading Space organisations, SpaceTrak is a fully queryable database used for market analysis, failure/risk assessment, spectrum analysis and space situational awareness (SSA).

For more information go to www.seradata.com/spacetrak

Related Articles

NORAD to track Santa again

As part of the Christmas celebrations, NORAD (North American Aerospace Defence Command) is attempting to track Father Christmas (Santa Claus) Read more

Musk plans a stock offering for SpaceX after successful IPOs in his other firms

Elon Musk, the billionaire Internet, clean energy and rocket entrepreneur who made his initial fortunes in the internet business, most Read more

US military once planned to explode atom bomb on Moon

There has been much tabloid interest in what is a re-release of the revelation originally made by the protect's leader Read more

Opinion: ESA has chosen badly with respect to its launch vehicle development

ESA really had three choices with respect to its launch vehicle development: it could built the Ariane 5 ME which Read more

Musk goes for methane-burning reusable rockets as step to colonise Mars

While speaking at the Royal Aeronautical Society in London in November, the billionaire former Paypal Internet executive, Tesla electric car Read more

No space predictions (or space errors) in Skyfall as James Bond serves his country well (Updated)

While the latest James Bond adventure Skyfall (Director: Sam Mendes) does use a lot of 'Big Brother' surveillance technology to Read more

History: UK gave up impressive space programme including plans to launch UK astronauts “just to get into Europe”

There will be sadness in those "space cadets" in the United Kingdom of all ages as we note that new Read more

Opinion: The madness of imprisoning earthquake scientists may halt satellite seismic forecasting research

To world scientific dismay, on 22 October, seven scientists working at the Italian National Commission for the Forecast and Prevention Read more

Cookies & Privacy

Click here to read about use of cookies on the website

Categories

Archives