Water deja vu
Recently, a video of the next trials of the landing of the Orion ship appeared.
It shows the impact test in the event of a strong side wind. The video is beautiful, but it causes a serious feeling of deja vu - the same tests of the same kind of Apollo module took place in the same (if not the same) pool fifty years ago. And, since then the technology was only being created, it was more interesting to watch those tests - the ship tumbled and even sank.
The penultimate test
The test on August 25 was the ninth and penultimate on the plan in this series of tests. The capsule hit the water in a “lateral” position, with a serious horizontal speed and falling more than five kilometers per hour faster due to the simulated failure of one of the three parachutes. Test dummies, which in normal landing should be pressed into the chair, this time shifted to the side. Sorry, the video shows only the views outside. But in the old recordings of the 60s, you can find shots that were shot from the inside.
Separately, it should be noted that now full-scale tests are used mostly to confirm the parameters obtained on computer models. In the 1960s computers were worse, and full-size models were not cheaper than today's ones, so large-scale (reduced) models were used.
At the end of the video, tests of landing the model on a hard surface are shown. The idea of planting the Apollo on land and not on water was not widely considered, but, nevertheless, many materials in the archives with tests of just such a landing (from 9:25).
After the reduced models, it was the turn to test Apollo's full-size models. And then the engineers were in for a surprise - in the first test, the command module drowned (from 10:31).
The hull's strength calculations turned out to be wrong - it just cracked from a blow. In the video above, you can estimate how big the crack was, once the dummies were doused with a rather large flow of water. Engineers had to redo the design and carry out additional tests in different conditions, with the fixation of the process with multiple cameras (from 11:31).
And, returning to Orion, its tests seem a bit boring, because the probability of such errors is less by an order of magnitude, and you already know in advance that the test will probably be successful.
Roll and balls
If you carefully watched the video, you might be wondering - why does the capsule touch the water, usually with a roll? The answer is actually quite simple - with a zero slope, an almost flat heat shield would lead to a tougher impact flat. And with a roll the capsule enters the water gradually, and the overload from the impact is noticeably less.
And if you watched photos and videos of Apollo landing, you probably noticed three balls in the upper part of the capsule. Their purpose is also quite simple. When planting the capsule could turn over, and this situation would be stable. This, for example, happened to Apollo 11 (from 2:43)
We had to add inflatable bags that would have sought to lift the nose of the device up. Funny, but exactly the same bags are on Orion.
Despite the keen sense of deja vu, the spectacle, especially with epic music, is still pretty. In the second test, by the way, we see a coup upside down, which is not corrected, because inflatable bags were not placed on the test capsule.