pseudocode can be developed from rules of thumb.
    pseudocode: enter radius of moon orbit, moon velocity, gravity constant 
    pseudocode: output mass of earth in kilograms, metric tons
    pseudocode: need diameter of moon orbit also
    pseudocode: rules of thumb can be 3 to 15 percent off, partly since g..in g..out.
    pseudocode: need test cases > small,medium, giant
    pseudocode: need testcases within range of expected operation.
    pseudocode: are there any cases too small or large to be solved? 

        # pretty print from autoindent and ased editor
        # Planet Mass Calculator
        # written on Windows XP on eTCL
        # working under TCL version 8.5.6 and eTCL 1.0.1
        # gold on TCL Club , 2may2014
        # comment follows from gold, 12Dec2018
        # pretty print from autoindent and ased editor
        # Planet Mass Calculator V2
        # written on Windows XP on TCL
        # working under TCL version 8.6
        # Revamping older program from 2014.
        package require Tk
        namespace path {::tcl::mathop ::tcl::mathfunc}
        frame .frame -relief flat -bg aquamarine4
        pack .frame -side top -fill y -anchor center
        set names {{} { radius of lunar orbit  meters:} }
        lappend names { velocity of moon in orbit  meters per second:}
        lappend names { gravitational constant  m**3/kg-sec*sec: }
        lappend names { answers: lunar orbit diameter meters  :}
        lappend names { earth mass kilograms :}
        lappend names { earth mass kilograms :}
        lappend names { earth mass metric tons:}
        lappend names { earth mass metric tons:}
        foreach i {1 2 3 4 5 6 7 8} {
            label .frame.label$i -text [lindex $names $i] -anchor e
            entry .frame.entry$i -width 35 -textvariable side$i
            grid .frame.label$i .frame.entry$i -sticky ew -pady 2 -padx 1 }
        proc pi {} {expr acos(-1)}
        proc about {} {
            set msg "Calculator for Mass of Planet V2
            from TCL ,
            # gold on  TCL Club, 12Dec2018 "
            tk_messageBox -title "About" -message $msg }
        proc self_help {} {
            set msg " Planet Mass Calculator V2
            from TCL Club ,
            # self help listing
            # problem, Planet Mass Calculator V2
            # 3 givens follow.
            1) radius of lunar orbit  meters:
            2) velocity of moon in orbit  meters per second:
            3) gravitational constant  m**3/kg-sec*sec:
            # Recommended procedure is push testcase
            # and fill frame,
            # change first three entries etc, push solve,
            # and then push report.
            # Report allows copy and paste
            # from console to conventional texteditor.
            # For testcases, testcase number is internal
            # to the calculator and will not be printed
            # until the report button is pushed
            # for the current result numbers.
            # >>> copyright notice <<<
            # This posting, screenshots, and TCL source code is
            # copyrighted under the TCL/TK license terms.
            # Editorial rights and disclaimers
            # retained under the TCL/TK license terms
            # and will be defended as necessary in court.
            Conventional text editor formulas
            or  formulas grabbed from internet
            screens can be pasted into green console.
            # gold on  TCL Club, 12Dec2018 "
            tk_messageBox -title "Self_Help" -message $msg }
        proc calculate { } {
            global answer2
            global side1 side2 side3 side4 side5
            global side6 side7 side8 testcase_number
            incr testcase_number
            set lradius $side1
            set lvelocity $side2
            set grav_const $side3
            set diameter1 [* $lradius  2. ]
            set side4 $diameter1
            set mass [/ [* $lradius $lvelocity $lvelocity ] $grav_const ]
            set side5 $mass
            set side6 $mass
            set side7 [* $mass .001 ]
            set side8 [* $mass .001 ]
            return $side5
        }
        proc fillup {aa bb cc dd ee ff gg hh} {
            .frame.entry1 insert 0 "$aa"
            .frame.entry2 insert 0 "$bb"
            .frame.entry3 insert 0 "$cc"
            .frame.entry4 insert 0 "$dd"
            .frame.entry5 insert 0 "$ee"
            .frame.entry6 insert 0 "$ff"
            .frame.entry7 insert 0 "$gg"
            .frame.entry8 insert 0 "$hh" }
        proc clearx {} {
            foreach i {1 2 3 4 5 6 7 8} {
                .frame.entry$i delete 0 end } }
        proc reportx {} {
            global side1 side2 side3 side4 side5
            global side6 side7 side8 testcase_number
            console eval {.console config -bg palegreen}
            console eval {.console config -font {fixed 20 bold}}
            console eval {wm geometry . 40x20}
            console eval {wm title . " Planet Mass Calculator V2 Report, screen grab and paste from console 2 to texteditor"}
            console eval {. configure -background orange -highlightcolor brown -relief raised -border 30}
            console show;
            puts "%| table |printed in| tcl wiki format|% "
            puts "&| quantity| value| comment, if any|& "
            puts "&| testcase number| $testcase_number||& "
            puts "&| radius of lunar orbit, meters:| $side1 ||&"
            puts "&| velocity of moon in orbit, meters:| $side2||& "
            puts "&| gravitational constant m**3/kg-sec*sec :| $side3||& "
            puts "&| answers:  lunar orbit diameter meters :| $side4 ||&"
            puts "&| planet mass kilograms:| $side5||& "
            puts "&| planet mass kilograms:| $side6 ||&"
            puts "&| planet mass metric tons:| $side7 ||&"
            puts "&| planet mass metric tons:| $side8 ||&"
        }
        frame .buttons -bg aquamarine4
        ::ttk::button .calculator -text "Solve" -command { calculate   }
        ::ttk::button .test2 -text "Testcase1" -command {clearx;fillup 3.75E8 1000. 6.67384E-11  7.5E8  5.6E24 5.6E24  5.6E21 5.6E21 }
        ::ttk::button .test3 -text "Testcase2" -command {clearx;fillup 3.75E8 1000. 6.67384E-11  7.5E8  5.6E24 5.6E24  5.6E21 5.6E21 }
        ::ttk::button .test4 -text "Testcase3" -command {clearx;fillup 3.75E8 1000. 6.67364E-11  7.5E8  5.6E24 5.6E24  5.6E21 5.6E21  }
        ::ttk::button .clearallx -text clear -command {clearx }
        ::ttk::button .about -text about -command about
        ::ttk::button .self_help -text self_help -command { self_help }
        ::ttk::button .cons -text report -command { reportx }
        ::ttk::button .exit -text exit -command {exit}
        pack .calculator  -in .buttons -side top -padx 10 -pady 5
        pack  .clearallx .cons .self_help  .about .exit .test4 .test3 .test2   -side bottom -in .buttons
        grid .frame .buttons -sticky ns -pady {0 10}
        . configure -background aquamarine4 -highlightcolor brown -relief raised -border 30
        wm title . "Planet Mass Calculator V2"      



  

  puts " %| testcase $testcase_number | value| units |comment |%"
  puts " &| volume| $volume| cubic meters |based on length $side1 and width $side2   |&"