(Much of this is from an email Joel Scotkin sent to ARocket on Thursday)
We had a tremendous day yesterday, and the team did an absolutely phenomenal job. We’ve been a little bit quiet during the competition period, but (especially given all the press around yesterday – Bloomberg turned our office into a broadcast studio with XoiE in the background) it seemed like a good time to post an update on the last couple months of development.
First of all, yesterday’s flights. The whole morning went off without a hitch. I was pretty nervous at 6:30 am – winds were pushing 30 knots. Ben faked confidence that “on calm mornings, it gets windy when the sun comes up, and on windy ones it calms down in the sun.” I didn’t believe him at all, but did get the judges to agree that high winds would be a valid condition for a “temporary weather hold” if needed. Fortunately, we didn’t need it – Ben was right or lucky. Setup went much more smoothly than last time, much of the morning spent letting the judges do their final survey, painting the X-Prize logo on the pads, etc. Beyond starting with the vehicle completely detanked and depressurized, it pretty much felt like a normal test day.
When the clock started, operations went much faster than our first attempt a couple of weeks ago. We still had one hiccup – we have a cascade fill helium cart with six helium tanks of various levels of remaining pressure, and miscalculated the total pressure we could get with the leftover tanks on the cart – had to swap out tanks right as we started loading. We’ve got plenty of tanks – for a timed competition we should have just stuck six full tanks on the cart and worried about it later. Lost 10+ minutes there, especially because the helium fill is more or less the critical path – overheating the composite tanks is a real worry as Armadillo noted. We’re using a chiller we borrowed from XCOR – the helium runs through a coil in a dewar of liquid nitrogen, lets the fill go much faster.
Both flights went off so smoothly they practically felt routine. The wind calmed down just before our first flight (I think the tower radioed us 17 knots, but it was intermittent – definitely less for the flight itself). On the first leg we landed practically in the feet marks from our first attempt. The return flight (which we had never run before) was only interesting in that I knew the flight had a small dogleg turn (it doesn’t quite go in a straight line between the pads), and on the outbound flight the dogleg was on the far side of the middle pad from where I was. Ian hadn’t thought to mention that on the return flight it followed the mirror image of that path instead of going the same route – it looked pretty much like the rocket was heading straight for Ben, Ian and myself. Real moment of relief when it cut over to the pad on cue!
Total time (subtracting out judges holds) was about 1 hour 38 minutes, from our allotted 2:15. Would have been enough margin for a third leg. Level 2 will take longer for fuel and LOX loading, but doesn’t look like time will be a problem. I don’t think we’ve gotten final measurements yet, but the preliminary was 20.2 cm for the first flight and 11 cm for the second.
After lunch the judges came out and looked at our new Level 2 pad, measured and approved it. Our contractor got creative – the pad looks great. The surface has a cool “lunar surface” texture to it, the boulders are big granite stones he hauled in and set, and they put some cool impact rims around the craters.
Should be quite a show in the Mojave area last week of October – scheduled for six days, three teams. Best of luck to everyone.