Source of Acquisition• NASA Johnson Space Center

Global landing site access using atmospheric skip tra-jectories

L. Bryant

Abstract

Mars direct entry, without going into orbit, does not provide global accessto all landing site latitudes. Latitudes accessible via direct entry trajectoriesconsist of a ring around the backside of the planet, centered about Vinfinity. Landing sites outside this ring can be achieved using a modifiedapproach trajectory entering the atmosphere over the South Pole"aerocapture fashion" that will skip out to an altitude above the atmosphereand then re-enter the atmosphere a second time and continue to toward theNorth Pole. The first aerocapture maneuver is aligned to provide an exitorbit that contains the desired landing site with an apoapsis computed toprovide proper ranging for the second entry. A powered maneuver isutilized during the exoatmospheric phase to remove altitude and flight pathdeviations due to uncertainties in the atmosphere occurring during the firstentry. Three guidance schemes are required for global landing site accessanalysis. Aerocapture guidance was used for the first atmospheric entry,Shuttle Powered Explicit Guidance was used for the exoatmosphericmaneuver, and Apollo Derived Entry Guidance was used for the secondatmospheric entry. An altimeter to update the onboard navigation stateafter the first atmospheric entry, was required to remove accumulated dead-reckoning navigation errors and achieve reasonable range errors at chutedeploy.

Lee Bryantlee.e.bryant 1 @jsc.nasa.c,ov281-483-8170

EG5/NASA Johnson Space Center2101 NASA Rd 1Houston, TX 77058

cn

OO

OW

A%

k

T MM

%

0 CL

CD

r,

(D CD

00

CD

--I

C/)

rm

tL

CD 0 0 (D

Cl) Fn

'

Cl)

0

CD 0 rMIL

0

s. 5

o

Alti

tude

(km

)D

5D

100

150

200

250

o° 0 0 ^m

°o0

iv

Q o

O>

c ^m m

o0

a m

0

a CO

i

2 m m Fg

DD

yti y^

00

II

vv00

0 °o

D Cin r v

Ci

0 0

o.

7 Q

N^, 7

o m =

O p J

o m

7

7 ^ Q0 a

O Oom

O m

7 .+ 7

O O X

^ C

7 ^

r, 7 fl'

(p 7

m In

.^ V

m j n

0 O

N /l e1X

m A

m

4L_ k R

^s

i 9

Si° Ir5

S^

^a 3 O

26 w

O C

Declin

ation

(deg

)- r

o' d

pO

r<a

— -

-p a

ry ,

—m

:v 4

dl ^

tat ^ G

{Q

m 2r

CD

m _

c _

7 s

m

O

A--

E3-

--

--

r -

T- ------

-- -I

ma

'4

- o

^

^ ^ a

C77

------------

- 3 o

N3 0

od a

c ----- - ---- ----

c ^f

nn ^

^ c

, `<

J<

<» 6

I_

n-

a

N m

c^

Cn

ai

°o n

ai

0 3

al

-S

q.-C

D0

^ w

Ifm

--- _Z -- --

----*- --V1

7

-m W

Q

3S

°^ 10

n

m^

Ln

rn

W ^l (J _T N ^J

y1^ •

O

.uos^

y

4oY.

J

CD

CD

CD

0I

CD

O

C M..r

•

i

H

O O

oc

Vl

Vl

^--^

WJ

W

00

V^

-O!^

^O

A^

^N O

^

CD

(^ '^u

OS

r r

CD

^

^D CL n O n O n O O V1

^0-

O n ^D n CA

I ^, z b a

rA^

p^^

+)

¢,r+

Jlz

Q }•CC

N

UP

^^

b^

Ou

e^ O

'^^.

n/b

^O

-^O

N

CD

^^ o

O

CA

^

`""y.

k^

M^

^^

^la

m]

CS

O

G^

•

(D^-

+

S'

•CD

F~-+

•1

!"''.

lam

•^

I--+

•N

n

""0r

e J

^• ^

s i

Y'

R rt Y m I I

+

Y'

n o R

R

Y

r- CD C^

n 0 R Y

l J

V M^ r

I^ •

M^ • r V

y n O

Nr-

rrt

O^

N^

Ne--r

oR

^n

Ro

^

R^*

R;^

+Nm ^-

C/1

cDo

I IC'

1o

^ Q..

CD ^-S C

U^.

oN J O

IIII Y'

Y>

+

Y^

Y.

N

C

CD

^. O

O ^

O (^

'^ O

CD ^ CD O CO C AD

O A^ cn r-r

n r--r O

i

^\

Dy2

CD

CD

^C

CD

OO

f1.

p ?O

CD

Tr

C

n^

C7^

NSID

C7

0'^

'-3

++

/yn

NN

V^^'1^

•^

IIfl

1-C

ID

^^

c

.^ ^

oQo

A^

CD

^IImo ^

^V,

It

r..r

•

I^ •

V

3`R

sI

y(^7

-7-1

1>

C%

^^"

IIII ,

.-;

^o

YN

o

0

OU

QQ

-cn

CD

CD

(^

cn

nO

Y

nr

O'^

CD

IIy

II r

C^'

YN N

n'YN

e--r

r^ ^

Y>

r

Y

n O z cn x

II

b n O n O P^ r c

C^^

IIII

III

n x`^

c 0 cx u

C^

C^

r—f-

CC

D^C

^ N^'

N^'

^ CD

r+ ^'

^C CD O

CD v'.

^ UG

O CD ^

nr ^- C

^, o n

^ o

C ^

UQ O

~

'

^1.

U4 Sy ^ n

n O n

^^ C7

U^ O e--r

CD

s i

Oz

OCD

0Z

pz 000

°Z

Z

rm

7z

70

rl

r10

0 OZ M

Oz n 0

rn

OMNI •

^71

(D C) QL)

IZ 0 D

Irz

(D (D Q Co (D

co

(D 0 3CL

(D D

co

m CQ (D 0 0 3 3

CD

^n

CD

rD

r+

CD

C^

CD

C O

n

''^

O O

CD

r-►

rD

rD

rD^ ^ n

CD

CD

Zr+

n

O

rCD

O CD

CD

ri

rD

CD

rD rD P7-

CD CD

5^

CD

CD

►.^

CD

.rD

CD

CD

rD

Omni

•ar

a O O r..

^I

^I

^I

I^^

r^

v,v

'W

^^.

Nc.

^^

riO

n'

np

D('D

^-+

EEL

^I

^N

^N

"^,"

"rf'D

W`^

SID

~!

^'

St'D

77-

O

pp

CD

rn

nM-

rC

Dn CD

A^

a"

CfG

^'

W

O W CD n O CL

V)

C I^ •

Mme+ 'u

or^

4 5

/ :^^

n,

^b R4^eVh,t^

^«^^

3365!m

ae

-14%)

u,

,w

,

)^

§ t

>

\

(`

@

/k )

% }k

/[

p `}5 }\ ƒ2

\w

\

< ~ƒ\

^>\ § \

^ k

^ §

^ D C |K

^®

^ D

k d— ^m-^r -^—^.^ ,—«a=—

^,az-^

® k \

^

mN

mGamma

w*) am

m

rn x> #

& a(

\§

/`k

}`/\

^°

f

^\

%§ ^

!

>^

§

§[

^ ^ ^ rot-M n ^ ^ ^ ^ ^ ^ ^ ^

^

^ ^ ^ ^-^ ^ ^ ^-^

^^ ^ ^ ^ ^ ^ ^ ^ ^

w= ^

rr

»em \

w ^

w^

>wr

w*

rJ

>

}§

r

\

d %»^ »

d

'.

y

>®

\

\^ ^\

olRN Vebdt

,,c i

Kep

l2rmare_

ko,)

N3vARLde

crt Keoa nxin o

_t,—"

33203=5

_9

ZTY)

Imb

N)16

37,71 ,

m

195

a

m210

2b

^^(

Defto

lo'ekntvfrun^^_r

rrc-ieuver

1rr^k

,^i

141

UT.'. rrc-it mow

e r

1111

IDY.

,40

511

0171-

1-D.3

UCO

a2

CD

CD

e(

/B

IT

/^§^

\) \

G

IMI

till

>

71?

Tr_

mi

1,; 3v 4cicc

at ErrtrVhtaf^

(kuo)

WkLe

33407 ,395

RW

35

MM

Nt

3CO

3425

34,V

to0

to

21

m-f

fl

45

VFI

FA

C^l

FT1

No

Dce?

.-riRjrqf

.ri

t Er

trd

Intf

iwe

(k1)y

Nj.,-Garrunri

at &)try Irterfat

(deg)

—1954

—)152

—1656

—IQ

—9E46

—IFA4

—ifA2

—IW

I—als

—33

11—32D

—3.15

—3.10

CL

RR

R

at

1>

1>

O O ^71

O

Otis

m w <^

rCm«¥2=@a

A-b&+mam__.

,>

,!

««

+«

mm

«aa

~\

*x

^+

.>

(k

~`

»

!} §6

±

§^

\^

*>

; !| C7

1NivA«,±^^

>

^!

»mI^^&tommm

^l

C \`

ao ^

&^

A} }^ \\

ƒ`

k

^:

\§ { ƒ® `

2 &^

»

sw

^w

:r

rm ¥

^ .->

w

,,

r

> mw^,

»x< : \,w®

w

\&

»w

®, ,

^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^

d

q

CD

d n^

--r

O

I^

WW

^N

Oc^

OO

^

UP

CD

CD s O n^ n CD

C7 CD

Ir •

O CD

UG CDA)

CD

A+ O J C1

t—F

UG CD

CD

.uo

f'd

k

5

^.^,,

.!"^`

"^ ^..

I

°°^^

^,,\

j

A^

n^

N:^

^w

N:".

'O

O^

C..

rD

z"

a d

"n

CD

CD

CD

r^^

CD (D

r) CD r

nrD

dY

^.

~Y

CD I.a n

o^

CD w

^C

7y^

.a

00

,

"y

c â̂tO

<. C

N7a

dn

top

'L7

CD

CD

a-

.cnK

^^

^^

ad

oo^^c>

a^

a^

a

^a

^CD

Ca

^^

^'o x

^>

(DCD

r-^^t

^d

^_̂

.^

NO

cJi

CIS

n •

O U

^Q

O

Op

`ti

CD̂.^

CrJ

o o

nz a

nC

WP

ao

o

CL

CD

o^^

^c

00

rD

cn

CA

oo

CD

aCD

,rDCD

bcn

~^

rD

00CD

oa

-f'

na

aIn

0000^

Oo^

-°a°

o`D

cnCA

oa

arD

oFD

NCD

CD U

^N

aa a

0n

^a

aa

Iv

Oa

o0

En

xo

b

n y a°o,

Dispersions

SWGTOI = 5.4467 / 0.38% 3 sigma Weight

DSPC1 -0.050 / 10% 3 sigma Cl

DSPC2 = 0.0048 / 4% 3 sigma Cd

ALONG DEG = 0.1 / Longitude

GDLAT DEG = 0.1 / Latitude

VI = 5.0 / Velocity ft/sec

GAMI DEG = 0.05 / Gamma

AZI DEG = 0.1 / Azimuth

HD KM = 0.5 / Altitude

RNCPOS(1) = 1.0

12NCPOS(2) = 1.0 / Random number in covariance, position

RNCPOS(3) = 1.0

RNCVEL(1) = 1.0

RNCVEL(2) = 1.0 / Random number in covariance, velocitN

RNCVEL(3) = 1.0

AABIAS(1) MTR 2.4525e-4

AABIAS(2) MTR = 2.4525e-4 / Accelerometer biases

AABIAS(3) MTR = 2.4525e-4

AMISAL(1) = 4.84814e-6

AMISAL(2) = 4.84814e-6

AMISAL(3) = 4.84814e-6 / Accelerometer nonortho/misalign

AMISAL(4) = 4.84814e-6

AMISAL(5) = 4.84814e-6

AMISAL(6) = 4.84814e-6

AASCAL(1) = 1.0e-4

AASCAL(2) = 1.0e-4 / Acceleration scale factor

AASCAL(3) = 1.0e-4

GDRIFT(1) DEG = 8.3333e-7

GDRIFT(2) DEG = 8.3333e-7 / Gyro bias drift

GDRIFT(3) DEG = 8.3333e-7

GSFERR(1) = 1.0e-6

GSFERR(2) = 1.0e-6 / Gyro scale factor

GSFERR(3) = 1.0e-6

GMISAL(1) = 4.84814e-6

GMISAL(2) = 4.84814e-6

GMISAL(3) = 4.84814e-6 / Gyro nonortho/misalign

GMISAL(4) = 4.84814e-6

GMISAL(5) = 4.84814e-6

GMISAL(6) = 4.84814e-6

ROTN(1) = II1.0e-6

ROTN(2) = 111.0e-6 / Navigated attitude .^s f

ROTN(3) = 1 11.0e-6 j

5

Q

Type I and Type II

2007 Opportunity, Depart Earth 9/23/07 , Trip Time = 2 10 days, C3 Type I

Landing Lighting and Latitude for Direct Entry JSC Mars Sample Return (2007 Opportunity, Datemme September 23, 200712:00:00.0, Trip Time 210 Days)

V.lnfi"ty. 3 90 kml. 5<on .. , - 9O ! -~ - ~ ~ Inertial Entry VeloCity. 6 28 kmls 0 0 a a 0 COO 0 0 0 10 0 0 Direction of Planet Min Landing latitude· ·85 9 deg • I .. RotatiOn Max Landing Latitude = 42.7 deg - OJI/ ' D

- i 60 l"b ay OrO , land,ng """'.. II 'b

, 30 'lJ '\ - \ Q .

! v '6 '.1_ Q - -9.0 - 0 30 ' \

~ Night ~ ~O l'=' : / /1 ,

rEa'"

-60 ,,,-'( / V~W

'- h i ,~ _, C 0 .1 I (~IH- U _ J

Po.'g,.de Landing Rl rrograde Landing

Relative Right Ascension Measured from V-Infinity Vector (deg)

Sub-Solar POlf'lt

Sub-Ear1h Point

2007 Opportunity, Depart Earth 9/2 1/07 , Trip Time = 365 days, C3 = 12. 8 km2/s2 Type II

Landing Lighting and Latitude for Direct Entry JSC Mars Sample Return

Inertia~~;;;;:~~;;5~:~ Da,te/~ sep~:9L.:~07 ,12:r:

OO,O, ::~:~:::p:; Dlays) Min. Landing Latitude = -43 .2 deg Rotation Max. Landing lathude = 74.8 deg I [J (

I 60 f ll.-lD

ltt -:.;" · ~:ll:ll c;; Sub-Eh 0 ! V-Infinity ,IH ' c Vector 0 .2

r

1 '~liO T . i -30 Ii l ~

l (J l1nh'lJ,lb'b ' b

~ __ f

90

Night , 1 Landtng Access , -'~~tJ:~ j

-90 -~ Pasigrade Landing Retrograde L.ndlng

Relative Right Ascension Measured from V-Infinily Vector (deg)

LAlitWe(deg)

Type I

ElM View & D'~lght Elrth View & .. Hour. E.rth VIew & 8 Hour. E.rth View & Night OJlytGhl D.~lght Nlowed

Type II

EaM 'kw & D.)tght urth Yew & .. Hows Earth \tew & 6 HolM' Earth Yew & Night o.~t Oa~t Mowed

4LfF

-

O O

......

....

F

7

C,

gm

CD

-1 - ----

--

-------

----

Ij

T

II

Tcn

m4i

.

-T

-,-

-r-T

-

fJ

D—

ti—

ti—

(deg)

.1..

......

......7

0 to

CL,

IL

- E

L

---- -------

-

aw

n

01

----------

--

-

. .

. .

....

....

. . ..

.....

I ....

.....

..

fa

^f^

o

KD

o

o

rt rt

II

^f rt

=w *NEW

O