Feeds

Mixed bag of motors lifts India's budget Mars shot

Solid rocket boosters and hypergolic cocktails

The smart choice: opportunity from uncertainty

India's budget* Mars Orbiter Mission (MOM) last week thundered heavenwards from Sriharikota spaceport atop a Polar Satellite Launch Vehicle (PSLV), en route to a rendezvous with the Red Planet in September 2014.

PSLV-C25 blasts off. Pic: ISRO

PSLV-C25 blasts off. Pic: ISRO

Weighing in at 500kg, plus 850kg of fuel, the MOM spacecraft was well within the 1,800kg lifting capability of the PSLV-XL ("extended") variant tasked with getting it Marswards.

The PSLV is an interesting beast, boasting a mix of solid rocket and hypergolic engine tech.

PSLV-C25 on the launchpad. Pic: ISRO

PSLV-C25 on the launchpad. Pic: ISRO

Its principal first-stage thruster boasts a mighty 139 tonnes of hydroxyl-terminated polybutadiene (HTPB) bound propellant. Strapped around this core are six solid rocket boosters (SRBs), four of which fire at launch and two which fire around 30 seconds into the flight.

Such engines are a popular choice among the rocketry big-hitters. The European Space Agency's (ESA) Ariane 5 uses two SRBs to provide an extra kick up the backside. They burn ammonium perchlorate composite propellant (APCP) - aluminium powder and oxidising ammonium perchlorate held in HTPB.

The PSLV's second-stage booster is, by contrast, a locally built Vikas engine burning approximately 40 tonnes of unsymmetrical dimethylhydrazine (UDMH) and nitrogen tetroxide (N2O4).

The Vikas Engine. Pic: MTAR Technologies

The Vikas Engine. Pic: MTAR Technologies

Many nations are now ditching hypergolic cocktail burners in favour of engines using less volatile fuels.** Russia's long-serving Proton, for example, uses no less than 10 N2O4/UDMH motors - six in the first stage, three in the second and one in the third.

However, its planned replacement, the Angara 5 rocket, will rely on a kerosene/LOX-powered "Universal Rocket Module" first stage.

Similarly, China is eyeing kerosene/LOX for future versions of its Long March, which currently rise heavenwards thanks to N2O4 and UDMH.

Back at the PSLV, meanwhile, once the Vikas has done its job, seven tonnes of solid propellant power the third stage. After that, it's back to a hypergolic blend for the fourth stage, as two engines slurping monomethylhydrazine (MMH) and nitrogen oxides finally send the payload on its way.

The PSLV's exotic rocket motor mix has propelled it close to the top of the reliability league table. To date, it has executed "24 continuously successful flights", a performance described by the Indian Space Research Organisation as "superb". ®

Bootnotes

*£45m ($74m) - small change in Mars mission terms.

**For more on rocket motor propellants, see "Rocket boffinry in pictures: Gulp the Devil's venom and light a match".

Eight steps to building an HP BladeSystem

More from The Register

next story
Malaysian Airlines flight MH17 claimed lives of HIV/AIDS cure scientists
Researchers, advocates, health workers among those on shot-down plane
Mwa-ha-ha-ha! Eccentric billionaire Musk gets his PRIVATE SPACEPORT
In the Lone Star State, perhaps appropriately enough
The Sun took a day off last week and made NO sunspots
Someone needs to get that lazy star cooking again before things get cold around here
Diary note: Pluto's close-up is a year from … now!
New Horizons is less than a year from the dwarf planet
Boffins discuss AI space program at hush-hush IARPA confab
IBM, MIT, plenty of others invited to fill Uncle Sam's spy toolchest, but where's Google?
Microsoft's anti-bug breakthrough: Wire devs to BRAIN SCANNERS
Clippy: It looks your hands are shaking, are you sure you want to commit this code?
prev story

Whitepapers

Seven Steps to Software Security
Seven practical steps you can begin to take today to secure your applications and prevent the damages a successful cyber-attack can cause.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
Designing a Defense for Mobile Applications
Learn about the various considerations for defending mobile applications - from the application architecture itself to the myriad testing technologies.
Build a business case: developing custom apps
Learn how to maximize the value of custom applications by accelerating and simplifying their development.
Consolidation: the foundation for IT and business transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.