ESA lifting body entry vehicle on the cusp of final approval
BY STEPHEN CLARK
Posted: June 10, 2011
PARIS -- The European Space Agency should formally approve this summer the construction of an Italian-led demonstrator that will launch into space on a rocket, fly back to Earth like an airplane and parachute into the Pacific Ocean, according to the mission's project manager.
Artist's concept of the Intermediate Experimental Vehicle plunging back to Earth throught the atmosphere. Credit: ESA
The Intermediate Experimental Vehicle is on track to blast off on a Vega rocket in late 2013, speed around the Earth at a peak altitude of nearly 300 miles, then drop from space and fly back to Earth with the help of aerodynamic flaps and a parachute.
Giorgio Tumino, the IXV project manager at ESA, said the craft passed its final critical design review in May. Senior ESA officials are now firming up the spacecraft's cost before signing a contract with Thales Alenia Space of Italy to build the vehicle.
Formal approval for the contract signature should come from an industry planning committee meeting at the end of June, Tumino said in an interview.
"We are in quite an advanced stage of the program," Tumino said. "It's not paper, but it's reality. There is an internal European process for the approval of all the activities. We should be able to sign the actual contract by the end of this month."
Sandrine Bielecki, a Thales spokesperson, said the company signed an agreement to be the IXV's prime contractor in 2009. Individual contracts for design work and hardware production are handled separately.
After ESA and Thales sign a final production contract, there is a 27-month schedule planned to manufacture parts, build the spacecraft and test it before shipping the vehicle to the launch site in Kourou French Guiana.
The total cost of the mission is about 100 million euros, or about $143 million.
ESA has the money to build the spacecraft, but funding for Vega launcher will only come at the agency's next meeting of member states' ministers in late 2012. If ESA signs a launch contract then, IXV could be ready to fly in the fourth quarter of 2013, Tumino said.
"The objective now is to place the contract, build the vehicle and qualify it, then have it ready to be shipped to Kourou," Tumino said. "We really are now going to procure the contract for all the pieces necessary to run the mission. Now what we are missing at the next Ministerial [Council] is only the Vega launcher. We'll have all the pieces there to meet the launcher."
Construction should begin in September, according to Tumino.
The IXV program is emerging from a reorganization at the last Ministerial Council meeting in 2008. Italy increased their financial commitment to the project, and Thales Alenia Space of Italy was appointed prime contractor. An industrial consortium of EADS Astrium and Finmeccanica previously held the position.
The reorganization "induced some delays" as Thales Alenia Space got up to speed on the program, but now the IXV is ready to enter the production phase, according to Tumino.
Its mission will last just a few hours, but the IXV is a big step for Europe. The demo flight will not go into orbit, but the craft is a prototype for future vehicles that could service the International Space Station, land on other planets, or carry people to orbit.
The IXV mission builds on years of ESA development, including the Hermes space plane program shelved by Europe in 1992. Hermes was supposed to be Europe's version of the space shuttle, conceived as a mostly reusable ship able to carry people back forth to orbit.
Artist's concept of ESA's Hermes space plane. Credit: ESA
But no Hermes shuttle was ever built despite considerable technological developments in the program. ESA's atmospheric re-entry demonstrator mission in 1998 proved out the Hermes flight control algorithms, but the IXV will fly with more a more advanced heat shield and working aerosurfaces. And it's shaped more like Hermes.
The mission also recycles ESA's research for the NASA-led X-38 crew return vehicle, a lifeboat for the space station that was scrapped in the last decade.
The IXV will fly with approximately 28 advanced ceramic heat shield tiles on its belly, while white ablative material will insulate the top of the vehicle during entry.
With no wings and a peculiar blunt cigar shape, the IXV won't land on a runway like the space shuttle. Instead, the 16-foot-long ship will gently fall into the Pacific Ocean under a parachute, where it will be retrieved by the Italian Navy or a commercial vessel. There is no landing gear.
But even without wings, the IXV is shaped as a lifting body, meaning it can maneuver in the atmosphere through a series of roll reversals. Movements of two electromechanical body flaps at the rear of the vehicle will steer the IXV during entry.
It has a lift-over-drag radio of 0.7, giving the IXV "more controllability during flight, more maneuverability, and eventually a precision landing," Tumino said.
The craft's shape means it flies through the atmosphere instead of falling like a capsule.
Engineers are targeting an error ellipse of about 3 miles on the IXV mission, but follow-on vehicles could land with even more precision.
"This is a demonstration mission. We will be launching from Kourou with a Vega launcher, and we have a set of ground segment stations which will support the mission," Tumino said. "Where the vehicle meets the atmosphere, the conditions will be equivalent to a return mission from low Earth orbit, so basically a 7.5 kilometers per second [16,777 mph] entry speed, so that we can experience all the key environmental features of such a re-entry mission."
The craft's nose will pitch up 40 degrees during re-entry, and it will bleed off speed in a series of roll maneuvers like the space shuttle.
Once officials wrap up contract negotiations this summer, some of their attention will turn to studying applications for the technology to be tested by the IXV. Tumino said the analysis will help prepare a proposal to ESA member states for the continuation of the program after the 2013 demo flight.
"We see opportunities and the possibility to go into orbit and perform ground landings, so to have a retrievable and reusable system," Tumino said. "It's not the space shuttle, which has a huge cost because it's a huge system. It would have to be contained in cost so it would be affordable for Europe to pursue."