Road to Ubar Pa - Nicholas Clapp [65]
Our route was not all up and down. On the outskirts of the Rub' al-Khali, dune fields alternate with gently undulating ramlats, or sand plains. We cruised along the southern edge of the Ramlat Mitan, and by midday we reached the dry lake once fed by the Wadi Mitan. The temperature was in the comfortable low eighties, the air still, the day clear. We scanned the way ahead with binoculars. Somewhere out on this lakebed was a stretch of the Ubar road, discovered in 1930 by Bertram Thomas but overlaid now by recent tracks. If necessary, we could return later and seek it out. But for now, our plan was to keep moving. By day's end we hoped to intercept the road where it was well defined. We were equipped to survey and follow it for two, possibly three, more days.
Our Discoverys headed out across the lakebed, aiming for a cluster of dunes identifiable on our space imagery. It was a little unclear where to go next. We picked what appeared to be a fairly obvious route west, which led us into a winding dune street a hundred or so yards wide between parallel lines of dunes. We made good time. The dunes became higher and higher—so high they could no longer be crossed. We felt increasingly uneasy as the dune street angled us more and more to the north, farther and farther away from where we wanted to go.
On we went, flanked now by walls of great red dunes more than six hundred feet high. Nearly three hours after leaving Wadi Mitan, shielding his eyes against the low but still intense sun, Ron said, "Uh-oh," followed by, "Rats!" Ahead, the way was blocked by a massive wall of sand. We had driven into a huge cul-de-sac.
And it was us, not it, that was in the wrong place. We were lost.
Distracted by the challenge (and fun) of driving the sands, we hadn't stopped to fuss with compass bearings and land navigation. We had not paid heed to the fact that in this desert, as in all deserts, everything looks alike, and there is little or nothing (such as buildings, telephone poles, trees) to lend a sense of scale. From a distance, a small dune looks just like a huge dune. And features like slopes, ridges, and gullies are replicated over and over. With your nose to a map—or a space image—you can go for miles quite certain that you are where you're not, only to realize the error of your ways when you come up against an inescapably distinctive landmark. Case in point: the wall of sand before us.
We decided to camp where we were for the night. The next day, though we could ill afford it, we might have to retrace our route back to the Wadi Mitan and try another route west. We pored over a detailed Landsat 5 / SPOT image in search of our cul-de-sac. With a yellow grease pencil we marked three possibilities. None was even close to where we wanted to be.
That evening, Ron used three Kit Kat bars to illustrate that at any given time at least one NASA navigation satellite would be overhead. "But why the silence? I just find it hard to believe the whole system is down. What of ships at sea? What of animals with transmitters around their necks?"
"And what about people lost in the desert?" Kay added.
"There has to be some emergency provision," Ron convinced himself, and reached for the receiver, to be greeted again by "NOSATS FOUND." He grumbled and punched away at the keypad. "Aha!" he finally said, for he had discovered an advisory: in our part of the world, the system would be up and running once a day, between 2 and 3:30 A.M.
"Encouraging," Ron said, "provided these dunes don't block any signals." The Rub' al-Khali's darkly encircling dunes could easily stand between us and a satellite hovering low in the sky. Setting the receiver on the roof of a Discovery, Ron programmed it to switch on at the appropriate hour and automatically record our position.
Sunday, December