Margaritifer Basin (Margaritifer Trilogy Book 1) (87 page)

Jeff laughed. “Wouldn’t surprise me.”

“There’s a message from Chrissie;
she says the whole world is watching.”

“Oh great, an audience of seven
billion. Let’s try not to embarrass ourselves.”

Abby chuckled. “If we do, we’ll
probably be the only ones that never know it.”

Susan slapped the inside of Abby’s
leg. “Thank you for that encouraging observation.”

“You’re welcome. Jeff, we’re
missing cocktail hour.”

He glanced at his watch. “Not here.
It’s a quarter past four in the morning for cryin’ out loud.”

“Whatever. I could still use a
drink.”

“Yeah.”

#

“30 seconds,” said Gabe.

“Roger,” said Abby. “RCS armed?”

“A and B armed,” said Jeff

“Pyros?”

“Pyros A and B armed.”

“Gabe?”

“Go for sep. 20 seconds.”

“2.5 feet per second?”

“Yes.”

“Rog.”

“10 seconds. 5, 4…”

“Thrusting,” said Abby.

“2, 1… sep.”

“SEP,” said Jeff. He felt a gentle
shock as explosive bolts separated the lander from the ship. “The clock is
running. EI minus 180:00.”

“We’re clear,” said Gabe.

“Rog,” said Abby. “0.4, 0.9, 1.4,
2.0, and… shutdown.”

“2.5 on the EMS,” said Gabe. “Nice
driving.”

“Thank you.”

“Alright, back off to about 50
meters then do a manual RCS check. Coming up on seventeen minutes to deorbit
burn.”

“Rog.”

“Standby for manual RCS check,”
said Abby.

Jeff felt the lander roll, pitch
and yaw both plus and minus.

“Manual RCS is Go.”

“Rog,” said Gabe. “And auto RCS
check…” The flight computer performed the same series of checks. “Auto RCS is
Go.”

“Rog,” said Jeff. “Are we Go for
EDL?” He heard Gabe take a deep breath.

“Yes, we are Go for EDL.”

“Roger. Do you need to get a fix?”

“No, GDC’s aligned.”

“Rog. Okay, Abby, turn us around
and spin us up.”

“Rog, pitching.” Abby slowly
pitched 180º, orienting the lander for a retrograde burn of the approach stage
main engine. “And… rotation. 0.5, 1.0, 1.5, and… shutdown. 2.0 RPM.”

“Oh my god!” said Gabe. “I think
I’m gonna barf.”

“Just close your eyes for a minute
and try not to think about it,” said Jeff. “You’ve done this in the simulator.”

“Yes, I know. And what happened in
the simulator?”

Jeff laughed. “Um, you barfed.”

“Right.”

“But that was in gravity. Just
relax, think happy thoughts.”

“Do you know where we are and what
we’re about to do?”

“Uh, yeah.”

“Perhaps you could suggest a happy
thought.”

“Um, well, in a little over three
hours you’ll be walking on Mars, you’ll have gravity, no spinning, and a nice
comfy bed in the Genesis tonight.”

“Comfy bed?”

“Alright, comfy air mattress. In
any case, you won’t be in space anymore. How’s that for a happy thought.”

“Okay, allow me to dwell on that
for a minute.”

“Dwell away. Time to burn?”

“14 plus 25.”

“Rog. Range to Sundancer?”

“110 meters.”

“Do you have an image from that
little camera in the approach stage?”

“Yes. It’s in Video-3.”

Jeff punched up the image on his
display and watched as their home for the past seven months slowly drifted
away.

“That’s a little unnerving,” said
Susan.

He sighed. “Yeah.”

“Not as unnerving as it’s gonna be
in fourteen minutes,” said Abby. “Once we light the engine on this flying
saucer, there’ll be no going back.”

Jeff nodded to himself and stared
for a moment longer, not sure what to say. “So long old girl, see you in a year
and a half. Um, Gabe, here comes your state vector from Newport.”

“I see it. Hang on.”

He waited.

“Okay, looks good. We’re in agreement.
Abby, your sextant star is Shaula. Can you find it?”

“Shaula? Never heard of it.”

“It’s star 53.”

“Yeah, right, like I remember all
of them?”

“It’s in Scorpio’s tail.”

Abby groaned. “Can you just give me
the shaft and trunnion angles?”

“It’s already aligned. Just keep
that one in the crosshairs.”

“Okay, I’ve got it.”

“Engine ARM,” said Gabe. “PROCEED.”

Jeff glanced at the event timer.
“Okay, standby for 180-meter per second, twelve-minute four-second Descent
Orbit Insertion burn in twenty seconds. Next stop, the Margaritifer Basin.”

“Rog,” said Abby. “If there is life
down there, I hope it’s ready for some company.”

“Yeah.”

“Thirteen seconds,” said Gabe. “Ten
seconds… 5, 4, 3, 2, 1…”

“Ignition,” said Abby. “We’re
burning. 10%.”

“Roger,” said Gabe. “Thrust.
Looking good.”

“Rog. Throttling up. Attitude’s
good. Right down the pipe.”

“Roger. Delta-V is good. EMS and
G&N are together.”

“Gabe, pitch trim is down about a
degree.”

“That’s alright. We didn’t start at
full thrust. Give it a minute or so and it’ll pick up.”

“Rog.”

“Not a bad ride,” said Jeff.

“A lot smoother than launch,” said
Susan.

He chuckled. “I think the San
Francisco Earthquake was smoother than launch.”

“30 seconds,” said Gabe.

Jeff glanced at his heads-up
display. “Gabe, Delta-V looks good, don’t you think?”

“Yes. 174.76, right on the mark.
Abby, cutoff should be nominal.”

“Rog.”

“15 seconds… 10… 5, 4, 3, 2, 1…”

“Shutdown.”

“Roger,” said Jeff. “Engine ARM
OFF. Abby?”

“Residuals are all under 0.2 feet
per second. Gabe, you want me to make a note of these before I trim?”

“I don’t see why. I don’t think
anyone is going to be doing this again.”

“Good point. Trimming.”

“Gabe,” said Jeff, “time to Entry
Interface?”

“145 plus 20.”

“Oh boy, two and a half hours is a
long time to sit here and twiddle my thumbs.”

“Don’t you dare. I need you to keep an eye on the
gravimeter, and how it’s plotting relative to our predicted track. It’s been 50
years since Apollo and we still don’t have a good understanding of mass
concentrations, and they’re a lot bigger here than on the moon. The elevation
difference between the Syria Planum and the Valles Marineris is around 14
kilometers, and that doesn’t include the Olympus Mons and Tharsis Montes. Those
are some pretty substantial masses. Our track is relative to the MOLA, but all
those gravitational perturbations could pull us down or let us float up. We
need to hit EI at exactly 3,522.2 kilometers Mars radius, 569.35 kilometers
from our landing site, and a descent angle of 11.5º. If we’re not exactly at
that point, at that angle, at that moment, we could be in for a very long walk.
So, for the next couple hours, will you please pay attention?”

Jeff chuckled. “Yes ma’am. Do you
know who’s sitting FIDO today?”

“Supposed to be Jim, but Heidi drew
up that roster over a year ago. Could have changed by now, I don’t know. Why?”

“I was just wondering if they might
be any help if your mascon modeling was off a bit.”

“Well, it’s a certainty that the
model will be off by something. I mean, we aren’t even certain of the mass of
the masses. I think Jerry, Jim, Dianne, and Joanne did a great job with the
model, but the data points are still largely a guess. In any case, by the time
they even see an error, it will be too late to do anything about it. That’s why
we need to stay on our toes.”

“Gotcha.”

“Good. Sue, time to forget about
our vital signs and be a pilot.”

“Rog.”

“I’m going to slew the sextant
around to vertical and try and pickup our ground track. By the time we reach
EI, every second we’re off in hitting our navigational marks will be roughly a
mile long or short in our downrange landing position, and during hypersonic
aeromanuevering we can only compensate for so much. Let’s not make
Amos
drive halfway around the planet to find us. More than two seconds off on any
mark… I want to know about it.”

“Got it. Gabe, calm down. We’ve
practiced this a hundred times, and we all know what we have to do.”

“Okay. Sorry.”

#

“EI minus 40 minutes,” said Gabe,
“EDL Main.”

“Rog,” said Jeff, “System to Entry,
Descent and Landing mode, Main. Flight status poll. Flight dynamics?”

“Go.”

“Guidance procedures?”

“Go.”

“Propulsion?”

“Go.”

“Guidance, navigation and control
systems?”

“Go.”

“Crew systems?”

“Go.”

“Electrical generation and
illumination?”

“Go.”

“Instrumentation and
communications?”

“Go.”

“Data processing?”

“Go.”

Jeff sighed. “Okay, sounds like
we’re ready.”

Abby gave him a sarcastic chuckle.
“We better be, cause we’re long past the point of no return.”

“Uh, yeah.”

“Gabe, we’re still gonna go manual
on Approach Stage SEP and de-spin?”

“Yes. The computer will takeover at
balance mass jett immediately following de-spin.”

#

“Message from Newport,” said Jeff.
“Go for EDL.”

“What else could they say?” said
Abby.

“I dunno. Fasten your seatbelts and
hang on?”

“Funny,” said Susan, nervously.

“They also say JPL is passing out
the peanuts.”

“Why?” said Abby. “We’re a manned
mission.”

“Just wishing us luck,” said Gabe.

“Guess we should have brought some
peanuts.” said Jeff.

“I suppose. Entry Interface in 12
minutes. Two minutes to approach stage SEP. Abby, we’re a little high and hot.
Before we cut it loose, I want you to burn retrograde at 50% for four seconds.
Alignment is good. Whenever you’re ready.”

“Rog. Burning in 3, 2, 1, ignition.
And… shutdown.”

“Beautiful. Jeff, the approach
stage is all yours.”

“Roger. ASS in 90 seconds.”

Abby chuckled. “Best acronym we
came up with.”

Jeff laughed. “Yeah. Gabe, if we
just burn the AS RCS till it runs out of fuel, where will it come down?”

“I don’t know. If I had to guess,
about 500 miles east-southeast of the station, somewhere south of Beer.”

“But it would come down, wouldn’t
it? I mean, it’s not gonna make another orbit?”

“Oh, it’ll come down alright. Its
periapsis will still be well into the atmosphere.”

“Okay, then why don’t we just do
that? Give us plenty of separation.”

“Fine with me.”

“Roger that. Abby?”

“Okay. Ignition at EI minus ten
plus one?”

“Make it ten plus two,” said Gabe.
“We don’t want sep until we’re sure it’s burning.”

“Got it.”

“SEP in 55 seconds,” said Jeff.

“Rog. And we’ll de-spin immediately
following ASS?”

“Yes,” said Gabe. “Please.”

“Whiner. And we’ll follow that with
external balance mass jett?”

“Yes. We’ll need to be ready for a
state update at EI minus 9 minutes, which I’ll assess as soon as the AS is
gone, and then turn on final at EI minus 7.”

“Rog. Jeff, pyros?” said Abby.

“A and B armed. 25 seconds. God, I
hate this part.”

“What part is that?” said Gabe.

“Well, this approach stage cost
about $60 million, we used it for a bit over twelve minutes, and in fifteen or
twenty minutes it’s gonna be just another Martian impact crater out in the
middle of nowhere.”

“What did you want to do with it?”
said Abby. “Take it home and put in on the mantle? 3, 2, 1, thrusting.”

“And… SEP!”

“There she goes.”

“I feel my checkbook’s pain.”

Abby laughed. “It’s only money,
boss.”

“Right.”

“Okay, de-spin. Thrusting. 1.5,
1.0, 0.5, and… shutdown. Gabe?”

“Yes, we’re static.”

“ Alright, external balance mass
jett.”

“EBM JETT,” said Jeff. “Gabe?”

“Confirmed. Two balance masses
jettisoned. Standby for EI minus 9 state update… Star scanner and ground track
confirm G&N position, attitude, flight path angle, and velocity. Computer
is Go for Entry Interface. Ready for hypersonic aeromanuevering. Entry attitude
maneuver in 2 plus 20.”

“Roger,” said Abby, “2:20.”

“Seven minutes,” said Gabe. “Abby?”

“Turning on final.” Abby turned the
craft to ‘eyes in’. They were now flying backwards, the heatshield oriented
down their flight path. “We’re there.”

“Roger. We’re in the corridor. Bank
Attitude, HOLD.”

“HOLD.”

“Gabe, we’re not gonna run into the
MRO, are we?” said Jeff.

“No, not even close. It’s
approaching the South Pole, on it’s way to a daylight pass somewhere near
Gale.”

“Rog. Just wondering if we should
be watching for traffic.”

“At this altitude? Not likely. Nothing
this low would stay in orbit for long.”

“Got it.”

“Why is that?” said Susan.

“Because it’s only mid-spring down
there,” said Gabe. “In the summer the atmosphere heats up and expands. Anything
orbiting at this altitude would eventually run into the upper atmosphere and,
owing to friction, the orbit would begin to decay. And eventually, to use one
of your favorite terms, splat: bug verses Martian windshield at 4,000 meters
per second, and whatever isn’t incinerated upon entry gets scattered over a dozen
kilometers in bite-size pieces.”

Susan groaned. “Thank you. Too much
information.”

“You asked.”

“I did, didn’t I?”

“Uh huh.”

“Entry Interface,” said Gabe.
“4,714 meters per second, altitude 3,522 kilometers radius, 569 kilometers to
the landing site, four and a half minutes to chute deployment. Abby, 0.1 g’s.
Bank Attitude, AUTO.”