Launch Logistics: Speedy Rocket, Slow Electronics

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Sandra Joseph and Don Kight/NASA

NASA's GRAIL mission to study the moon launches aboard a Delta II rocket at Kennedy Space Center on Sept. 10.

Weird things jump out at me in press releases.

Take the press kit NASA prepared for the GRAIL mission. GRAIL consists of two nearly identical spacecraft that are on their way to the moon. Once there, they will make a precise map of the moon's gravitational field. Such a map will help scientists refine their theories about how the moon formed and what the interior is made of.

So I'm reading through the GRAIL press kit, learning about the size of the spacecraft (washing machine-sized), how long it will take to make the map (approximately three months), and where the mission control room is (at a Lockheed Martin facility just outside of Denver).

There's something oddly pleasing about a brand-new space mission launching with some rather old electronics.

I also learn that GRAIL can launch any day between Sept. 9 and Oct. 19. And then I get to this sentence:

"On each day, there are two separate, instantaneous launch opportunities separated in time by approximately 39 minutes."

That's weird. Now, I wasn't surprised that this mission had an extremely precise launch opportunity — "instantaneous" means the launch window is essentially a second long. I know you have to wait until the moon's orbit around the Earth, and Earth's orbit around the sun, and the Earth's rotation around its axis are all in exactly the right position before you can launch your rocket.

But what's up with two instantaneous launch opportunities. Why 39 minutes apart?

I called the NASA press office. They were stumped and promised they'd find someone who could give me the answer. In the meantime, I called several universities with large aerospace programs, and asked if anyone there had the answer.

Nope. Nada. Nothing.

So now this is beginning to bug me. I'm also beginning to worry. If an aerospace engineer can't figure this out, how am I ever going to understand it?

While I'm pondering this, GRAIL deputy project manager Tom Hoffman called. I asked him about the two instantaneous launch opportunities.

"It's a pretty simple answer not driven by the mission at all," Hoffman told me. "It's driven by the launch vehicle."

The launch vehicle? Not orbital mechanics or a complex trajectory? The problem, Hoffman said, is some slow electronics.

There is actually a launch window of 40 minutes or so each day. Modern computers in modern rockets can calculate the precise direction the rocket needs to launch on a second-by-second basis. But GRAIL was launching on a Delta II rocket, and Hoffman told me the Delta II rocket is a rather old design. It's been around for more than 20 years, "and so the rocket just can't, it can't do that internally, in its own computer system. It basically has to be fed all the information," he said.

Hoffman said it takes about 39 minutes to load in the new information, and then check to make sure that it was loaded correctly.

Not the answer I was expecting, but there's something oddly pleasing about a brand-new space mission launching with some rather old electronics.

Whatever works ... as the saying goes.

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All Things Considered–

A recent rocket launch sent NPR's Joe Palca on a mission himself: Why such precise launch times?

The agency says the satellite first penetrated Earth's atmosphere somewhere over the Pacific Ocean.

The United States isn't totally out of the woods; the possible strike zone skirted Washington state.

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HEALTH MANAGEMENT. NASA Unveils Next Generation 'Monster' Space Rocket

NASA

Artist concept of SLS launching.
If things go without a hitch, NASA said its newly unveiled Space Launch System could take its first manned test flight in 2017.
The new rocket design looks a lot like the Apollo era rockets that took American astronauts to the moon, but NASA said the new rocket is much more powerful than any other rocket they've made before and in conjunction with the Orion Multi-Purpose Crew Vehicle, already in development, it could set up astronauts for deep space exploration. The SLS will be NASA's first exploration-class vehicle since the Saturn V took astronauts to the moon.
"We're investing in technologies to live and work in space, and it sets the stage for visiting asteroids and Mars," NASA Administrator Charles Bolden said at a news conference.
 Enlarge NASA
Artist concept of future destinations.
NASA Artist concept of future destinations.
At the unveiling of the plans, Sen. Bill Nelson (D-FL) called it a "monster rocket."
According to the AP, Nelson put the cost of the program at $18 billion over the next five years.
"Will it be tough times going forward? Of course it is," Nelson said at the press conference. "We are in an era in which we have to do more with less — all across the board — and the competition for the available dollars will be fierce. But what we have here now are the realistic costs that have been scrubbed by an outside, independent third party."
The Houston Chronicle's SciGuy compares this new rocket to the old ones:

... The new space launch system will be much bigger and far more powerful. It will be able, initially, to lift as much as [154,000] pounds of cargo into space, nearly three times as much as the space shuttle, which had a capacity for about 50,000 pounds.
This is enough to lift space capsules, astronauts and the supplies they will need for voyages to the moon and possibly beyond.
The announcement comes after weeks of wrangling between the U.S. Senate and NASA and the White House. In the end the Senate seems to have gotten what it wanted, an affordable heavy lift system ready to fly by 2017.

"President Obama challenged us to be bold and dream big, and that's exactly what we are doing at NASA. While I was proud to fly on the space shuttle, kids today can now dream of one day walking on Mars," Bolden said in a press release.
NASA has a very technical description of the rockets, but the big thing to remember is that this new rocket marks a return to liquid technology:

The SLS rocket will incorporate technological investments from the Space Shuttle program and the Constellation program in order to take advantage of proven hardware and cutting-edge tooling and manufacturing technology that will significantly reduce development and operations costs. It will use a liquid hydrogen and liquid oxygen propulsion system, which will include the RS-25D/E from the Space Shuttle program for the core stage and the J-2X engine for the upper stage. SLS will also use solid rocket boosters for the initial development flights, while follow-on boosters will be competed based on performance requirements and affordability considerations. The SLS will have an initial lift capacity of 70 metric tons (mT) and will be evolvable to 130 mT. The first developmental flight, or mission, is targeted for the end of 2017.

Update at 2:36 p.m. ET. On The Money:
Money will determine whether that 2017 date is realistic, reports The New York Times. The paper says "if the space agency's budget remains flat, providing about $41 billion between now and 2025, then the first manned flight would not occur until 2021, and the rocket would fly only once every two years, and NASA would not finish the 130 metric ton version until after 2030."
The Times also adds that NASA does not yet have plans on how it could use the vehicle.
Update at 3:04 p.m. ET. How Much Can This Thing Carry?
A reader asks if this is really bigger than Saturn V, which was able to carry about 260,000 pounds into space. According to numbers the agency gave the AP, at its peak this rocket might be able to cary up to 150 metric tons into space. That translates to 331,000 pounds. If you take the 130 mT published on NASA's site that translates to 287,000 pounds; still more powerful than Saturn V.

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