Jake shook his head. You forgot the changed mass-ratio.
Oh...oh, yes! Kelly looked embarrassed. Mass-ratio...under power, the ship lost the weight of fuel burned. The thrust remained constant; the mass it pushed shrank. Getting back to proper position, course, and speed became a complicated problem in the calculus of ballistics. But you can do it, can't you?
I'll have to. But I sure wish I had Weinstein here.
Kelly left to see about his passengers; Jake got to work. He checked his situation by astronomical observation and by radar. Radar gave him all three factors quickly but with limited accuracy. Sights taken of Sun, Moon, and Earth gave him position, but told nothing of course and speed, at that time nor could he afford to wait to take a second group of sights for the purpose.
Dead reckoning gave him an estimated situation, by adding Weinstein's predictions to the calculated effect of young Schacht's meddling. This checked fairly well with the radar and visual observations, but still he had no notion of whether or not he could get back in the groove and reach his destination; it was now necessary to calculate what it would take and whether or not the remaining fuel would be enough to brake his speed and match orbits.
In space, it does no good to reach your journey's end if you flash on past at miles per second, or even crawling along at a few hundred miles per hour. To catch an egg on a plate don't bump!
He started doggedly to work to compute how to do it using the least fuel, but his little Marchant electronic calculator was no match for the tons of IBM computer at Supra-New York, nor was he Weinstein. Three hours later he had an answer of sorts. He called Kelly. Captain? You can start by jettisoning Schacht & Son.
I'd like to. No way out, Jake?
I can't promise to get your ship in safely without dumping. Better dump now, before we blast. It's cheaper.
Kelly hesitated; he would as cheerfully lose a leg. Give me time to pick out what to dump.
Okay. Pemberton returned sadly to his figures, hoping to find a saving mistake, then thought better of it. He called the radio room. Get me Weinstein at Supra-New York.
Out of normal range.
I know that. This is the Pilot. Safety priority urgent. Get a tight beam on them and nurse it.
Uh...aye aye, sir. I'll try.
Weinstein was doubtful. Gripes, Jake, I can't pilot you.
Dammit, you can work problems for me!
What good is seven-place accuracy with bum data?
Sure, sure. But you know what instruments I've got; you know about how well I can handle them. Get me a better answer.
I'll try. Weinstein called back four hours later. Jake? Here's the dope: You planned to blast back to match your predicted speed, then make side corrections for position. Orthodox but uneconomical. Instead I had Mabel solve for it as one maneuver.
Good!
Not so fast. It saves fuel but not enough. You can't possibly get back in your old groove and then match Terminal without dumping.
Pemberton let it sink in, then said, I'll tell Kelly.
Wait a minute, Jake. Try this. Start from scratch.
Huh?
Treat it as a brand-new problem. Forget about the orbit on your tape. With your present course, speed, and position, compute the cheapest orbit to match with Terminal's. Pick a new groove.
Pemberton felt foolish. I never thought of that.
Of course not. With the ship's little one-lung calculator it'd take you three weeks to solve it. You set to record?
Sure.
Here's your data. Weinstein started calling it off.
When they had checked it, Jake said, That'll get me there?
Maybe. If the data you gave me is up to your limit of accuracy; if you can follow instructions as exactly as a robot, if you can blast off and make contact so precisely that you don't need side corrections, then you might squeeze home. Maybe. Good luck, anyhow. The wavering reception muffled their goodbyes.
Jake signaled Kelly. Don't jettison, Captain. Have your passengers strap down. Stand by to blast. Minus fourteen minutes.
Very well, Pilot.
The new departure made and checked, he again had time to spare. He took out his unfinished letter, read it, then tore it up.
Dearest Phyllis, he started again, I've been doing some hard thinking this trip and have decided that I've just been stubborn. What am I doing way out here? I like my home. I like to see my wife.
Why should I risk my neck and your peace of mind to herd junk through the sky? Why hang around a telephone waiting to chaperone fatheads to the Moon numbskulls who couldn't pilot a rowboat and should have stayed at home in the first place?
Money, of course. I've been afraid to risk a change. I won't find another job that will pay half as well, but, if you are game, I'll ground myself and we'll start over. All my love,
Jake
He put it away and went to sleep, to dream that an entire troop of Junior Rocketeers had been quartered in his control room.
The close-up view of the Moon is second only to the space-side view of the Earth as a tourist attraction; nevertheless Pemberton insisted that all passengers strap down during the swing around to Terminal. With precious little fuel for the matching maneuver, he refused to hobble his movements to please sightseers.
Around the bulge of the Moon, Terminal came into sight by radar only, for the ship was tail foremost. After each short braking blast Pemberton caught a new radar fix, then compared his approach with a curve he had plotted from Weinstein's figures with one eye on the time, another on the 'scope, a third on the plot, and a fourth on his fuel gauges.
Well, Jake? Kelly fretted. Do we make it?
How should I know? You be ready to dump. They had agreed on liquid oxygen as the cargo to dump, since it could be let to boil out through the outer valves, without handling.
Don't say it, Jake.
Damn it I won't if I don't have to. He was fingering his controls again; the blast chopped off his words. When it stopped, the radio maneuvering circuit was calling him.
Flying Dutchman , Pilot speaking, Jake shouted back.
Terminal Control Supra reports you short on fuel.
Right.
Don't approach. Match speeds outside us. We'll send a transfer ship to refuel you and pick up passengers.
I think I can make it.
Don't try it. Wait for refueling.
Quit telling me how to pilot my ship! Pemberton switched off the circuit, then stared at the board, whistling morosely. Kelly filled in the words in his mind: Casey said to the fireman, 'Boy, you better jump, cause two locomotives are agoing to bump!'
You going in the slip anyhow, Jake?
Mmm no, blast it. I can't take a chance of caving in the side of Terminal, not with passengers aboard. But I'm not going to match speeds fifty miles outside and wait for a piggyback.
He aimed for a near miss just outside Terminal's orbit, conning by instinct, for Weinstein's figures meant nothing by now. His aim was good; he did not have to waste his hoarded fuel on last minute side corrections to keep from hitting Terminal. When at last he was sure of sliding safely on past if unchecked, he braked once more. Then, as he started to cut off the power, the jets coughed, sputtered, and quit.
The Flying Dutchman floated in space, five hundred yards outside Terminal, speeds matched.
Jake switched on the radio. Terminal stand by for my line. I'll warp her in.
He had filed his report, showered, and was headed for the post office to radiostat his letter, when the bullhorn summoned him to the Commodore-Pilot's office. Oh, oh, he told himself, Schacht has kicked to the Brass I wonder just how much stock that bliffy owns? And there's that other matter getting snotty with Control.
He reported stiffly. First Pilot Pemberton, sir.
Commodore Soames looked up. Pemberton oh, yes. You hold two ratings, space-to-space and airless-landing.