I read that Angara 5 will carry a "payload simulator" on its first test flight tomorrow Dec. 23, 2014. But the Indian GSLV mk.III recently flew for the first time with a prototype of the ISRO crewed spacecraft as payload. And SLS is planned to carry an uncrewed Orion around the Moon on its premiere launch.
Why not always use a test launch to test some real payload? Or is a simulated payload just another name for doing precisely that?
Launching on a risky booster, is risky.
You can define a risky booster as:
So you feeling lucky punk? How much development money are you willing to risk on any of those cases?
Why did ISRO take the risk on the GSLV launch and Angara5 won't? I would assume that ISRO wanted to launch that payload, their boosters are not cheap, their budget is not unlimited, and they needed a payload anyway to demonstrate it. If they do not demonstrate confidence in their own booster, who will be confident enough to use it?
The Russians launch often enough on so many different classes of vehicles that they are not lacking options for payloads. They may not have had some project that needed a cheap-to-free launch giveaway. Also Angara-5 is a fairly large payload booster (49,000 lbs to LEO), so to really test it out you need a fairly big payload. Big payloads are usually high value payloads.
At that point it becomes a better choice to literally launch a ball of steel, or container of water. Something cheap, with good sensors to characterize the details of the environment inside the launch fairing so customers know what to expect.
Now if you had say a propellant depot in orbit, and you had a tug, then it would have made a ton of sense to launch propellant for the depot. Value is low if lost, but nice freebie if it worked. But we don't.
As for SLS, it is so expensive, and will be launching so infrequently it almost cannot be 'wasted' on a test flight. That to me is a design flaw. It seems like a full up series of test flights before humans fly on it would be part of man-rating. Atlas V will have had 60 or 70 flights by the time a human flies in a CST-100. Falcon 9 will likely be at 20-30 flights before a human flies in a Dragon V2. Why is SLS going to do it on the second flight?
It will be interesting to see what SpaceX launches on Falcon Heavy as its first payload.
I personally would love to see Elon Musk's original goal, a greenhouse on Mars, as the first payload (Huge overkill since that was planned to be tiny, and F-H has a huge payload ability). That is the sort of 'waste' of money they could do as a publicity stunt for vaguely cheap inhouse if the booster needed a payload no one else would pay for.
In my time in Aerospace, we used "mass simulators" (lead or brass weights or water) for the simple reason that the actual payload (a satellite) wasn't ready yet. We try to get the launch vehicle and the payload ready for launch around the same time, which means both things are in testing at the same time, typically at different facilities, and they never meet until the final launch vehicle is assembled. For testing launch vehicles, the answer above is absolutely correct (cheaper to blow up a bucket of water than a satellite) - but for most uses of mass simulators, it's because the actual device isn't available. You can be sure that "uncrewed Orion module" is mostly mass simulators.
