STS-68, Endeavour, Space Radar Lab 2, Sep. 30-Oct. 11, 1994 September 4, 2013Posted by skywalking1 in History, Space.
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This month is the 20th anniversary of the Space Radar Lab 2 mission, STS-68. I was the payload commander, along with Mike Baker (CDR), Dan Bursch (MS2), Steve Smith (MS1), Terry Wilcutt (PLT), and Jeff Wisoff (MS3). An ambitious follow up to the successful STS-59, Space Radar Lab 1, SRL-2 was aimed at flying the multi-frequency, multi-polarized Shuttle Imaging Radar-C, X-Band Synthetic Aperture Radar, and the Measurement of Air Pollution from Satellites sensors in the northern hemisphere late summer, to compare SRL-1’s spring mapping results to those from a contrasting season of the year. STS-68 would also test radar interferometry, a technique to create highly accurate, three-dimensional maps of Earth’s topography. (More info at www.AstronautTomJones.com)
My crewmates and I rehearsed our countdown procedures at Kennedy Space Center on August 1, 1994.
Jeff Wisoff was seated to my left, close to the galley and side hatch. Note my clear helmet visor, indicating a “practice” helmet. We kept the dark visors for the real launch day, to avoid scratching them during our practice sessions like this one.
Our launch was planned on August 18, 1994, but at dawn on that date, when Endeavour’s main engines (SSMEs) ignited, the #3 engine violated a redline constraint, and the GPCs ordered an abort and engine shutdown. They automatically called for a shutdown when the discharge temperature on MPS SSME Main Engine #3 High Pressure Oxidizer Turbopump (HPOT) exceeded its redline value. The HPOT typically operates at 28,120 rpm and boosts the liquid oxygen pressure from 422 psia to 4,300 psia. There are 2 sensor channels measuring temperature on the HPOT. The B channel indicated a redline condition while the other was near redline conditions. The temperature at shutdown was at 1563 degrees R. while a normal HPOT discharge temperature is around 1403 degrees R. The redline limit to initiate a shutdown is at 1560 degrees R. This limit increases to 1760 degrees R. at T-1.3 sec (5.3 sec after Main Engine Start). Main Engine #3 (SN 2032) has been used on 2 previous flights with 2,412 seconds of hot-fire time and a total of 8 starts. This was the first flight for the HPOT on Main Engine (SSME) #3.
What all of this meant to me on the middeck (sitting next to Jeff Wisoff), was that as I felt the SSMEs rumble to life, I began mentally counting down the six seconds til booster ignition at T-minus-zero. Braced against the massive jolt of those SRBs exploding into life, I instead felt the engine vibration die away just as Terry Wilcutt shouted “Right engine down!”, accompanied by the blare of the master alarm. This meant serious trouble.
Out the hatch window to my left, I noted the gantry structure seeming to sway left and right under the vanished shove from Endeavour’s main engines–that was US swaying back and forth. Jeff and I hurriedly threw off our parachute straps and prepared to scoot across the middeck to open the hatch; we might all have to make a beeline to the escape slides on the far side of the gantry’s 190 foot level. We stayed on intercom, waiting for the word to egress.
Within the first minute, Launch Control had our pilots executing the pad abort checklist, entering computer commands that would stop the backup flight software from jettisoning our solid rocket boosters at T+2 minutes (embarrassing and deadly). As Jeff and I cleared our seats in the middeck and stood by to open the hatch, we heard reassuring words from Launch Director Bob Sieck’s team that the computers had executed an orderly shutdown, and no fire or explosion risk was evident.
“Damn! We’re scrubbed!” Jeff opined that we’d be set back at least three weeks by the necessary engine changeout. In fact it would take six weeks for our rollback, engine change, and rollout. STS-64 would slip ahead of us and fly in early September with its LITE laser sensor payload. Our new launch date would be Sept. 30, 1994.
The launch team did a superb job on our abort–the last pad abort in the space shuttle program, and the one that came hair-raisingly close to leaping off the pad with one engine down. That would have meant an immediate scramble to perform a Return To Launch Site (RTLS) abort, flying backward through our Mach 5 exhaust plume to attempt a dicey landing back on Merritt Island. If anyone could pull it off, it would have been Bakes, Terry, Dan, and Steve. Assuredly, no one wanted to try it first.
September 30 was set as our new launch date. STS-64 in the meantime had flown its successful LITE Earth-science mission, with the additional milestone of Mark Lee and Carl Meade test-flying the SAFER EVA jetpack. Our crew had taken a week-long vacation, then got back into simulations and recurring training to polish our space radar abilities. I thought we used the extra time to good effect, and we proceeded to the Cape even better prepared than we were in August. We were certainly more rested than on our first attempt.
One piece of bad luck befell us: on the day we entered quarantine, five of us came down with cold systems. We suffered through four days in Houston of runny noses, aches and pains, and sore throats, but with constant flight surgeon attention we slowly improved. Our flight to the Cape was on the Shuttle Training Aircraft, the Gulfstream jet, to spare our sinuses enroute.
When we arrived at the Cape, Dan Bursch stepped off the jet in his Groucho Marx disguise, telling reporters that our chances of avoiding a launch abort were better if Endeavour didn’t know he was in the launch area. Our spirits were certainly on the upswing as our three days in Florida at crew quarters drew to a close.
Our launch was timed for dawn on September 30, with Endeavour taking us into a 57-degree inclination, circular orbit, about 120 nm up. At that altitude our orbit would drift west at such a rate that we could image each of our science targets three times each day, from slightly different radar incidence angles.
The liftoff was exhilarating–this time I knew what to expect! I occupied the same seat as on SRL-1, with Jeff Wisoff to my left. No abort this time–the boosters came alive with a punch to the gut and we soared aloft. Much of the cabin dialogue we exchanged during launch is in my book, Sky Walking: An Astronaut’s Memoir. I’d asked that the side hatch window cover again be removed, so I had a terrific view of the gantry turning from gray, to red, to white-hot as the boosters lit. The following eight and a half minutes were punctuated by pyros firing to sever the boosters at two minutes, and then the attention-getting 3 g’s during the final minute of the ascent. During those final seconds I truly experienced the power of the space shuttle’s three main engines, just hurling our 100-ton orbiter toward the injection altitude and velocity. A miracle of technology and physics.
Below, another beautiful view of our dawn liftoff, as Endeavour jolts off the pad. During my second ascent to orbit, I was able to enjoy the physical and mental impressions a bit more methodically, recording my comments on a microcassette recorder during the eight-and-a-half minute climb to our 120 nm mapping orbit.
After MECO, it was off to the races, with Steve Smith and I teaming up on video and still photography of the external tank as it drifted away, below us. Then Jeff and I threw ourselves into converting the middeck into its orbit configuration, and getting the rest of the crew out of their suits and on into their orbital jobs. We had only about 5 hours until my bedtime; the Blue Shift of Steve, Dan and I were due for our first sleep period while Jeff, Mike, and Terry activated SRL-2.
Before launch, our crew had a chance to examine the Space Radar Lab and its SIR-C/X-SAR radars up close, nestled in Endeavour’s payload bay. C-band panels line the left edge, and the larger L-band panels cover most of the 12-m-long antenna. Along the port edge, next to the robot Canadarm, the German/Italian X-SAR antenna is folded downward toward the sill of the payload bay.
Below, SRL-2 is in orbit. Space Radar Lab 2 had some new wrinkles, added since our April flight of SRL-1. The JPL folks had added a gold decal that matched one the Germans and Italians had placed on the X-band antenna. And the Langley Research Center also added a label to their Measurement of Air Pollution from Satellites (MAPS) instrument, positioned right in front of the radar antennae. It all made for a spectacular view out the back windows of the cabin:
We also had about 160 radar imagery recording cassettes aboard, up from the hundred or so we took aloft on SRL-1. The radar imaging schedule was even more ambitious than in April–and I’d thought that was intense!
I had thought I was over my cold, but upon arrival in orbit and a night’s sleep, I ran into its aftereffects. My sinuses were clogged, and without gravity, NOTHING was coming “down” out of my nose. My head felt like a balloon, and my face was reddened as if by a sunburn. I took to the medical locker to find the decongestants, and over a week or so, I slowly improved. The rest of my crewmates also dealt with the congestion lingering from our colds, and the natural stuffiness from the fluid shift headward, caused by our transition to free fall.
Jeff Wisoff, assisted by the pilots and coordinating with Mission Control (MCC), got SRL-2 up and running on his long first shift in orbit. When I woke from my quick 6 hours of sleep and talked to Jeff, I found he’d been “running” flat out with the activation for his entire shift, barely having time to grab a drink or a quick snack. I got cleaned up in a hurry and took over with Dan and Steve as quickly as we could, to spell the Red Shift from their labors. Having been up more than 18 hours, they were understandably tired. We tucked them into bed and ran with our Science Timeline, our program of observations.
We discovered the tile damage on the first day of the flight, after opening the payload bay doors and inspecting the cargo bay. MCC determined that the heat loads on the upper half of the OMS pod were mild enough that the tile damage would not be dangerous. That greatly eased our minds. It was several days later that we discovered the source of the damage, looking up through the window and noticing a missing piece of tile just outside the outer pane. The tile tore loose during ascent and flew back to strike the OMS pod.
The radar imagery returned resulted in wonderful images, like the one below, all across the disciplines of the Earth sciences. As we woke for our first work shift, Jeff, Terry, and Bakes called us upstairs to see a spectacular volcanic eruption in Kamchatka. Everyone grabbed a camera to capture images out the windows, while the radar lab obtained thousands of detailed images, revealing details obscured by the eruption plume.
The eruption was a true serendipitous gift from nature. If we had launched in August as planned, we would have missed this rare geological event. Now we had a ringside seat.
Our wide-angle 90mm lens on the Linhof camera captured the view below. The Linhof produced a 4×5-inch film negative, with incredible detail. Each magazine held 100 frames, and we refilled magazines with fresh film inside a light-tight bag, stowing the exposed film in canisters and manually spooling a new roll into the magazine. The film reloading was part of our nightly housekeeping routine. But it was hard to tear ourselves away from the windows!
We were able to monitor Kliuchevskoi’s eruption for a solid week, using the SRL to track eruptive phases as weather fronts came and went across Kamchatka. During a TV downlink to MCC, I described how the radar beams interacted with lavas of varying roughness, using three samples from Hawaii to illustrate the viewing geometry. I had chunks of aa, pahoehoe, and andesite lava aboard–in free fall, I had to take care to not release rock dust or slivers of lava into the cabin from their ziploc bags. The andesite sample was a more viscous, stiff lava, erupted from some of the more recent cinder cones on Mauna Kea.
Our shift work was 12 hours on, an 8-hour sleep shift, plus 4 hours for “post-sleep” and “pre-sleep”. In those periods, we talked things over with the Red Shift guys, had breakfast, dinner, and exercise, and took care of necessary housekeeping. One of the challenges was giving Jeff, Terry, and Bakes a good night’s sleep by keeping quiet in the middeck. Even opening a locker could wake up that crew in their sleeping bags, inside their bunks, so we tried to get our lunch like church mice, then eat on the flight deck. Once I dumped a chunk of scrambled eggs that I’d insecurely anchored to a tortilla–it went flying all over the flight deck, and Dan had to help me gobble up the floating egg debris. Dan’s homemade chocolate chip cookies crumbled in their ziploc–getting them out without crumbs floating everywhere required true astronaut skill. From home, with the help of the JSC Space Food Lab, I’d brought TastyKake chocolate cupcakes and Butterscotch Krimpets, enough snacks to carry me through the 11-day mission.
The area above is my stomping grounds, the region where I grew up, and I can see my entire youthful experience in this single photo, from the Appalachians to the Atlantic Coast. I grew up in Baltimore, and now live and work near Washington, DC. So much U.S. history is also captured in this shot, from the formative moves toward independence in 1776, to major battlefields of the Civil War, to the great Emancipation in 1862 and at the Civil War’s close. During WWII, the Martin aircraft factory in Baltimore built the B-26 Marauder bomber, and in the 1960s produced the Gemini-Titan II boosters that jump-started my space interests. During the mission, my brother watched me soar overhead in Endeavour before dawn from his home in Fredericksburg, VA, in the Chesapeake region.
When we reached orbit on Sept. 30, ’94, the Taklamakan Desert was a major landmark and science target for Space Radar Lab 2. Our radar targets were the alluvial fans and dune fields along the southern margin of the Taklamakan, where the Silk Road oases hosted caravans and travelers on an ancient trade route. Note the alluvial fans and vegetation in foreground, fed by streams from the Altyn-Tagh mountains bordering the desert on the south. Our radar images found traces of Silk Road irrigation channels and sand-covered villages.
All of us enjoyed our repeated views of San Francisco Bay and the San Andreas Fault, running left to right in the bottom of the image below. Steve Smith and Jeff Wisoff were both Stanford grads, and Mike Baker hails from this part of the country. Urban growth patterns and the many tectonic faults and features were the focus of our radar and camera studies here.
Below, the Front Range of the Rockies is visible in this shot, focused just north of my alma mater, the U.S. Air Force Academy. The dramatic rise of the Front Range, in stark contrast to the Colorado plains, is apparent from overhead. I could also see at a glance several familiar airports–Buckley Field, Stapleton International, and the new Denver airport–I frequented during my Air Force flying years. Early snows top the highest peaks to the west.
Above, from STS-68, SRL-2, the Panama Canal Zone, seen in Oct. 1994. Note the Pacific at left, with Panama City. Colon is on the Atlantic Coast (Caribbean) at right. The dark green jungle area protects the watershed that supplies the canal with fresh water via the Chagras River and Gatun Lake, at the canal’s midpoint. We were about 120 miles up over northern S. America when we took this shot. (NASA STS068-327-099)
On Space Radar Lab 2, the region below was one of our bread-and-butter science regions, full of radar targets for SIR-C and X-SAR. During training I’d visited several geoscience teams, studying alluvial fans on the margins of Death Valley, lava flows from young volcanic vents near Barstow, and a snow pack science lab near the summit of volcanic Mammoth Mountain. This frame captures that entire region, a fascinating Earth science laboratory. Make sure you visit Furnace Creek in Death Valley, and swim in the hot-spring-fed pool there.
In the test above, Steve had a laser on his headstrap, and his job was to rotate his head to put the laser dot on a series of targets about 6 feet away on the middeck lockers, forward. The sequence of pointing was random, and the package Steve was wearing recorded his eye motions as well as his response and pointing time. Looks a little like The Terminator if you ask me. Mike Baker helps with the checklist. Note the tortillas in the ziploc bag on the Middeck Equipment Rack (MER) behind Baker, with the galley to the right.
When I enlarge the photo, I see my crew notebook also velcroed to the lockers above Mike’s left shoulder. And I’m actually visible behind Mike, taking a look out the side hatch window (or scrubbing the bathroom!).
We landed from this mission 20 years ago (10-94), but there are still surprises in the film shots (15,000) we took of Earth. Mono Lake is clearly visible above in this southwesterly view across the Basin & Range toward the Sierras. Beyond Mono Lake in the Sierras is the gateway to Yosemite Valley. Walker Lake is visible at lower right. South of Mono Lake is a chain of volcanoes, the Inyo Craters, leading toward the ski resort of Mammoth Mountain (ski trails are visible on the summit). To the upper left of Mono Lake is the tadpole-shaped Lake Crowley, in the oval basin called Long Valley Caldera. 700,000 years ago, that volcano erupted meters of ash all over the southwest US in a “supervolcano” eruption. The valley still smolders today with steam vents and carbon dioxide seeps. This is a spectacular part of the USA, and one of our science supersites on STS-68, SRL-2.
Below: The dark blue basin on the right of Crowley Lake is the Long Valley caldera, its oval, volcanic rim running NW to SE.
The Sahara was always full of mystery and visual treasure (below). The rust-red Tifernine Dunes are a Sahara landmark for space crews, imaged ever since the Gemini missions in 1965-66. Isolated in the midst of these sand and rock vistas are lofty volcanic peaks, like Tibesti, seldom visited by ground explorers. Several asteroid impact craters are also easy–and thrilling–to see. Sometimes while over the Sahara, you could convince yourself that the huge expanse of tan, yellow, and orange sands in view must be those of Mars.
We used Space Radar Lab 2 to measure from space the glacier motion on these Andean snowfields, using a technique called radar interferometry. Science aside, it was a visual treat to see these jewel-like icebergs adrift in the turquoise, glacier-melt waters of these fjords. A few years later I observed such glaciers up close in Prince William Sound and Glacier Bay National Park, Alaska. Rarely did shuttle missions reach the high (57-deg orbit inclination) latitudes we experienced on the Radar Lab flights, treating our crewmates to these unforgettable views of far southern S. America.
Australia’s landscape is as extensive as the continental U.S., and in the early “down under” spring of 1994, wildfires raged in several locations. This area of Queensland was particularly drought-ridden, and the fires were targets of our STS-68 carbon monoxide pollution sensor, MAPS. Aboard Endeavour, we photographed wildfires and smoke plumes for comparison with the MAPS data, and radioed reports of these carbon monoxide sources to the science team in the SRL payload operations control center in Houston.
The recorders were adapted from digital tape machines that flew in recon aircraft to record digital imagery data. One of the three on our flight deck failed about 8 days into the mission, so Jeff and Steve removed it and replaced it with a spare recorder that’d been flown up underneath our middeck floor. Pretty handy mechanics. Within 4 hours they had the new machine up and running again.
It’s rare to get a cloud-free pass above the Alps. Below, Lake Geneva dominates the center right; Geneva city is at the left, narrow end of the lake. Lake Geneva is fed by the Rhone River, with its spectacular right-angle turn to the east upstream from the lake. At far right center is Lake Neuchatel; Berne is just out of view, to the right. Lac du Bourget is the small lake left of center. Lyons is under the clouds at upper left. Here in early autumn, the snows have not moved into the Alps as yet, but a few high glaciers are still beautifully evident to my crew. Our radars imaged the glaciated Alps to study the motion of these ice “rivers” over time.
And now, halfway around the world, to China:
We looked repeatedly on our passes over China for any visible signs of the Great Wall, but even viewing enlargements of these prints, looking at where the Wall should be, proved fruitless. The wall is made of stone or earth that matches the local landscape, and would only cast a long shadow under ideal lighting conditions. So, only with the eyes of Ed Lu can you see the Great Wall of China from space.
Just after wheels stop on Endeavour, I was to unstrap from my middeck seat and stand up. The blood pressure measurement gear would record my response to standing erect in 1-g, once again. I knew when the equipment was working when my left arm’s pressure cuff inflated, but it never recovered after touchdown. The taped data from entry, however, were good, and so was the audio tape I made as we rode back through the atmosphere. I have to give credit to the designers for creating a rig that would work inside our pressure suits, and yet still be easy enough to don and operate. After return to Houston, I sent the investigators an apology for the verbal tirade I recorded, grousing about the troubles I had getting the batteries replaced and activating the system. My only excuse was being up for a very long day…around 18 hours by the time we landed, and we still had postflight medical tests to endure.
STS-68 is a highlight of my speech, “Sky Walking: An Astronaut’s Journey” — contact me at http://www.astronauttomjones.com/#!tom-jones-speaking-testimonial/cfgv