Mission To Mars Scenario Newcastle Academics Space Agency (NASA) is aiming be the first international agency send humans Mars. They have developed an extremely small and fast space craft carry your team. Unfortunately it is not big enough carry an assembled vehicle (buggy) explore the Martian surface. This means that your team will have assemble the buggy on site. Aim The aim of this full-day activity is build a suspension system for a simple Mars buggy that will allow a load be safely conveyed across the undulating Mars surface. Points are awarded for the distance and time your buggy travels before the load falls off. What do Your team needs design and build a Mars buggy from the materials provided: one of the two drilled timber bases (chassis), lengths of threaded rod (axles), plastic arms, wheels, string, nuts, bolts and rubber bands. The suspension system must make the buggy safe, reliable and stable. Carefully consider the number of wheels and where they are positioned. The number and attachment location of the strings used pull the buggy across the surface will also be important. Rules Each Mars buggy must include one of the timber chassis and roll over the test surface on wheels i.e. no part of it can scrape the test surface. The buggy must have string attached so it can be pulled over the surface. The string must feed through the metal guide at the end of the test surface. The buggy must not uch the vertical sides of the track. The distance between the left and right side wheels of the buggy cannot be greater than the length of one threaded rod. The test load must sit on its end i.e. with its smallest surface sitting on the rubber-faced wood block, on the p of the buggy. The test load must not be held or supported in any way. One buggy must be used for all official tests, i.e. your team can t use one buggy for load #1 and a different buggy for load #2. Scoring If your team is successful in carrying load #1 and #2 the entire length of the test surface (regardless of time) then you can attempt carry the large bonus load (#3). Your team will get an additional 50 points if your buggy is able carry the bonus load the entire length of the surface in under three minutes. There are 20 bonus points available at the end of the session for disassembling the buggy, returning the components, and leaving your area tidy when instructed. Tips Your team must focus on the suspension and mechanical layout of the buggy so that the load does not fall off the buggy as it is pulled along the surface. 1
STUDENT NOTES Mission To Mars The problem The aim of this activity is build a suspension system for a Mars buggy that will allow a load be safely conveyed across the undulating Mars surface. Points are awarded for the distance and time your buggy travels before the load falls off. Duration This activity runs for a full day (approximately 4 hours). Terms There are some terms used in this activity that you may not be familiar with: Mars buggy The wheeled vehicle you construct from the materials supplied. Suspension A system of springs and other devices that stabilise and insulate the body of a vehicle from the shocks transmitted through the wheels. Chassis A vehicle s main support frame on which the suspension, body and (in a real vehicle) engine and drive train are mounted Materials Your team will be given a choice of the two drilled timber blocks (chassis), lengths of threaded rod and eye screws. Wheels, rubber bands, string, nuts, bolts and various shaped plastic arms are also available. Rules 1. Each buggy must include one timber chassis. 2. The buggy must be conveyed over the test surface by wheels i.e. no part of the buggy can scrape the test surface. 3. The buggy must have string attached so it can be pulled over the test surface. 4. The pull-string must feed through the metal guide at the end of the test surface. 5. The buggy must not uch the vertical sides of the track. 6. The distance between the left and right side wheels of the buggy cannot be greater than the length of one threaded rod. 7. The test load must sit on its end i.e. with its smallest surface sitting on the nonslip rubberised wood block (which may be attached the buggy), on the p of the buggy. The test load must not be held or supported in any way. 8. If any of the eye screws are removed from the timber, they must be replaced at the end of the activity. 9. Only one buggy can be used for official times, i.e. your team can t have one buggy for load #1, and a different buggy for load #2. 2
Scoring The buggies can be trialled all day but will only be awarded points during the official test period wards the end of the session. The first official test involves placing the smallest test load (#1) on the rubber faced test pad on the buggy. Remember, the load cannot be held in position in any way. The team s chosen navigar will stand at the guide end of the Mars test surface and, running the string attached the buggy through the metal guide, pull the loaded vehicle along the surface. The time taken and the distance covered ( the point where the load falls off) are used determine each team s score. This process is repeated for the larger load #2. Load #2 is worth more points than #1. Your team may have several attempts at each load but only the best score for each load is counted ward your team s tal. If your team is successful in carrying load #1 and then load #2 the full length of the test surface - regardless of time - then your team has ONE attempt carry the largest load (#3). Your team will get an additional 50 points if your buggy is able convey the bonus load the entire length of the surface in under three minutes. 20 points will also be awarded each team that disassembles their buggy, returns all the parts, and leaves their workspace tidy. Tips Don t forget bring these notes with you the Challenge. Initially, use each timber block try several different suspension configurations and decide which one use. The following points should be considered: Changing the length and shape of the plastic arms will affect the stability of the buggy. Changing the location of the pivot point on the plastic arms that support the wheels will also change the performance of the suspension system. The placement of the pivot points needs be considered, as well as the direction and distance the plastic arms move. The number and position of the wheels affects the buggy s performance. Springs deform when a force is applied, and then resume their original shape once the force is removed. Rubber bands act in a similar way. When selecting rubber bands for the suspension system, the effect of the bands length and thickness needs be carefully considered. Flexible connecrs, such as string, are able support weight when pulled (put in tension) but not when pushed (compressed). 3
Once satisfied with the suspension configuration, your team should focus on the mechanical tuning of the buggy. The following questions may help: How far should moving parts travel? Should they be limited in some way? Does the ride height (ground clearance) of the buggy affect its performance? What is the best number and location of the attachment point(s) for the string that is used pull the buggy along the test surface? How much force is needed prevent movement or return the suspension its original position? What is the best location of the load along the timber chassis: ward the front, in the middle, or at the back? 4
SCORE SHEET Mission Mars School name: *Refer the back of this score sheet for the lookup tables convert time/distance points. Load #1 (Smallest load) Attempt number Distance (cm) Time (seconds) Points scored* 1 2 3 4 5 6 Best score (A) Load #2 (Medium load) Attempt number Distance (cm) Time (seconds) Points scored* 1 2 3 4 5 6 Best score (B) Bonus load, #3 (Largest load) Attempt number Distance (cm) Time (seconds) Points scored (tick one) 1 attempt only Full length Less than 3 min. If successful 50 If unsuccessful 0 Bonus points (C) Additional 20 points for disassembling and returning parts (D) FINAL SCORE = A + B + C + D = 5
Lookup Table Load #1 Time (s) Distance (cm) 0.0 2.9 3.0 3.9 4.0 4.9 5.0 5.9 6.0 6.9 7.0 7.9 8.0 8.9 9.0 9.9 10.0 11.9 12.0 13.9 14.0 15.9 16.0 17.9 18.0 19.9 20.0 21.9 22+ 15 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 30 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 45 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 60 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 75 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 90 83 81 79 77 75 73 71 69 67 65 63 61 59 57 55 105 103 101 99 97 95 93 91 89 87 84 81 78 75 72 68 120 123 121 119 117 115 113 111 109 107 104 101 98 95 92 88 135 143 141 139 137 135 133 131 129 127 124 121 118 115 112 108 150 163 161 159 157 155 153 151 149 147 144 141 138 135 132 128 Load #2 Time (s) 0.0 2.9 Distance (cm) 3.0 3.9 4.0 4.9 5.0 5.9 6.0 6.9 7.0 7.9 8.0 8.9 9.0 9.9 10.0 11.9 12.0 13.9 14.0 15.9 16.0 17.9 18.0 19.9 20.0 21.9 22+ 15 20 19 18 17 16 15 14 13 12 11 10 9 8 7 5 30 30 29 28 27 26 25 24 23 22 21 20 19 18 17 15 45 40 39 38 37 36 35 34 33 32 31 30 29 28 27 25 60 50 49 48 47 46 45 44 43 42 41 40 39 38 37 35 75 70 69 68 67 66 65 64 63 62 61 60 59 58 57 54 90 93 91 89 87 85 83 81 79 77 75 73 71 69 67 61 105 113 111 109 107 105 103 101 99 97 95 93 91 89 87 80 120 133 131 129 127 125 123 121 119 117 115 113 111 109 107 100 135 153 151 149 147 145 143 141 139 137 135 133 131 129 127 121 150 173 171 169 167 165 163 161 159 157 155 153 151 149 147 140 6