Firms re­visit the space cap­sule

Boe­ing, SpaceX return to proven de­sign in de­vel­op­ing space­craft.

Austin American-Statesman Sunday - - TECH SUNDAY - By Sa­man­tha Ma­sunaga

In 1961, an American astro­naut reached space for the first time and soared through the heav­ens in a gum­drop-shaped cap­sule.

Since then, peo­ple have flown to the moon, cre­ated space planes and de­signed rock­ets that return to Earth for pre­ci­sion land­ings. But when as­tro­nauts lift off next year from U.S. soil for the first time in six years, their ve­hi­cle of choice will be an­other cap­sule.

Boe­ing Co. and SpaceX are re­ly­ing on the tried-and-true de­sign as the two com­pa­nies each de­velop space­craft un­der NASA con­tracts to ferry as­tro­nauts to the In­ter­na­tional Space Sta­tion.

De­spite the sleek space­ships of sci-fi imag­in­ings or the fa­mil­iar winged body of the shut­tle, en­gi­neers have re­turned to the seem­ingly clunky cap­sule again and again for a sim­ple rea­son — it works.

“The cap­sule is a very durable tech­nol­ogy,” said Matthew Her­sch, as­sis­tant pro­fes­sor of the his­tory of science at Har­vard Univer­sity. “It may not be ro­man­tic to fly, but it’s go­ing to get you there and back safely.”

Since the end of the shut­tle pro­gram, the U.S. has re­lied on Rus­sia to trans­port its as­tro­nauts to and from the space sta­tion in the Soyuz space­craft, an­other cap­sule.

Boe­ing and SpaceX said they are confident their ve­hi­cles will fly next year, de­spite re­cent re­ports from the U.S. Govern­ment Ac­count­abil­ity Of­fice not­ing that de­lays for the two com­pa­nies have pushed the first test flights past the ini­tial dead­line.

The new space­craft have a num­ber of fea­tures that weren’t avail­able on ear­lier capsules — touch­screen dis­plays, large win­dows, more pow­er­ful elec­tron­ics and lighter ma­te­ri­als.

The space­suits that as­tro­nauts will wear also have been slimmed down. SpaceX has re­leased sev­eral pho­tos of its space­suit, which Chief Ex­ec­u­tive Elon Musk said

was tested to en­sure as­tro­nauts would stay safe even if the pres­sure in the cap­sule dropped sud­denly. Boe­ing’s “Boe­ing blue” space­suit is about 40 per­cent lighter than pre­vi­ous suits, and the gloves were specially de­signed to let as­tro­nauts in­ter­act with touch screens.

In the early days of the U.S. space pro­gram, as­tro­nauts lamented rid­ing in any­thing that al­lowed for such limited hu­man con­trol. Bor­row­ing the name from some­thing you swal­low didn’t en­hance the ap­peal.

Ini­tially, there was great en­thu­si­asm for mak­ing those space­craft look like air­planes, but it was dif­fi­cult to cre­ate wings that could nav­i­gate var­i­ous parts of a mis­sion and sur­vive the heat of re-en­try, Her­sch said.

Any space­craft rated to carry hu­mans has a spe­cific set of re­quire­ments. It must be ef­fi­cient in its vol­ume with enough space for all nec­es­sary life systems, but have as low a mass as pos­si­ble. It also has to with­stand tremen­dous G-forces, pres­sure and heat dur­ing launch and re-en­try.

The heat shield on a cap­sule’s blunt, slightly curved bot­tom helps pro­tect the crew as the ve­hi­cle re-en­ters the at­mos­phere.

Capsules are aero­dy­nam­i­cally sta­ble when trav­el­ing at su­per­sonic speeds dur­ing re-en­try and re­quire lit­tle ma­neu­ver­ing to return to Earth in an emer­gency, giv­ing them “in­her­ent sta­bil­ity,” said David Giger, se­nior di­rec­tor of Dragon devel­op­ment en­gi­neer­ing at SpaceX.

“What’s re­ally in­ter­est­ing about cap­sule de­sign is it’s aero­dy­nam­i­cally ef­fi­cient both on as­cent and de­scent,” said David Barn­hart, di­rec­tor of the USC Space En­gi­neer­ing Re­search Cen­ter. “It only takes one event to take it back down, which is es­sen­tially a re-en­try burn, and that’s good be­cause it min­i­mizes mov­ing parts and com­plex­i­ties.”

In cre­at­ing space­craft for NASA’s com­mer­cial crew pro­gram, both Boe­ing and SpaceX have built on the ex­am­ple of their pre­de­ces­sors.

Boe­ing con­structed its de­sign based on some of the data from the 1950s- and 60s-era Mer­cury and Gem­ini, as well as NASA’s Orion, a crew space­craft that first flew in 2014 and is slated to ride into space atop the agency’s Space Launch Sys­tem rocket in 2019.

Rob Ad­kisson, Boe­ing’s chief en­gi­neer for the com­mer­cial crew pro­gram, said the CST-100 Star­liner’s com­pact cap­sule de­sign matches its mis­sion as a “peo­ple mover,” com­pared with the larger space shut­tle that es­sen­tially func­tioned as a “truck back and forth.”

“It looks a lot like Gem­ini and Mer­cury,” he said of the Star­liner. “But it’s quite a bit dif­fer­ent.”

The Chicago aero­space gi­ant’s Star­liner will blast into space on an At­las V rocket be­fore de­ploy­ing and dock­ing au­tonomously at the space sta­tion. When re­turn­ing to Earth, the space­craft will jet­ti­son its ser­vice mo­d­ule, de­ploy para­chutes to slow down and drop its heat shield so the ve­hi­cle’s air bags can in­flate for a softer ground land­ing.

One ma­jor devel­op­ment is the fine-tun­ing of the cap­sule’s heat pro­tec­tion. The Star­liner’s base heat shield has an ab­la­tor, a pro­pri­etary ma­te­rial that ab­sorbs en­ergy on re-en­try and only chars “like a marsh­mal­low,” said David Schiller, leader of Boe­ing’s com­mer­cial crew aerostruc­tures in­te­grated prod­uct team.

The base heat shield and its four back­shells lo­cated around the crew ve­hi­cle are made of com­pos­ite ma­te­ri­als. A glass-phe­no­lic hon­ey­comb core is wedged be­tween the com­pos­ite lay­ers, like an ice cream sand­wich, to pro­vide high strength while stay­ing light­weight. The en­tire ve­hi­cle is cov­ered with ther­mal pro­tec­tion, in­clud­ing a type of wo­ven ce­ramic “blan­ket” sim­i­lar to the ones used on the space shut­tle, and ce­ramic tiles on the back­shells to de­flect heat.

Like Boe­ing, SpaceX also looked to pre­vi­ous capsules when it first em­barked on its Dragon space­craft.

Back then, the com­pany, head­quar­tered near LA, was still very young, so en­gi­neers looked at the lega­cies of the Mer­cury, Gem­ini and Apollo pro­grams. The lessons are in­cor­po­rated in its Dragon 2 crew trans­porter cap­sule, along with those learned from de­vel­op­ing SpaceX’s Dragon 1 ve­hi­cle, cur­rently used by NASA to take sup­plies to the space sta­tion.

The Dragon 2’s abort sys­tem is a marked change from the cap­sule used in the Apollo pro­gram, which used a rocket on a tower lo­cated at the top of the cap­sule and was dis­carded on the way up to or­bit. SpaceX’s launch abort sys­tem can be used at any time dur­ing the as­cent and stays on the cap­sule so it can be re­cov­ered on splash­down — part of the com­pany’s em­pha­sis on reusabil­ity, said Giger of SpaceX.

The SpaceX cap­sule will also uti­lize more au­to­ma­tion, such as its dock­ing abil­ity, to im­prove safety and al­low the crew to fo­cus on cru­cial tasks, Giger said. The com­pany is also work­ing on de­vel­op­ing the cap­sule’s pre­ci­sion land­ing ca­pa­bil­ity in the ocean so re­cov­ery crews can ar­rive within min­utes.

“Just be­cause it looks like a cap­sule does not mean the in­her­ent tech­nol­ogy is the same,” Giger said.


David Schiller (left) and Rob Ad­kisson of Boe­ing ex­am­ine a cap­sule heat shield com­po­nent be­ing tested for the CST-100 Star­liner cap­sule. The Star­liner is be­ing de­vel­oped to trans­port as­tro­nauts to the In­ter­na­tional Space Sta­tion.

Newspapers in English

Newspapers from USA

© PressReader. All rights reserved.